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Hemocyanin

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Hemocyanin, copper containing domain
Hemocyanin2.jpg
Single oxygenated functional unit from the hemocyanin of an octopus
Identifiers
SymbolHemocyanin_M
PfamPF00372
InterProIPR000896
PROSITEPDOC00184
SCOP21lla / SCOPe / SUPFAM

Hemocyanins (also spelled haemocyanins and abbreviated Hc) are proteins that transport oxygen throughout the bodies of some invertebrate animals. These metalloproteins contain two copper atoms that reversibly bind a single oxygen molecule (O2). They are second only to hemoglobin in frequency of use as an oxygen transport molecule. Unlike the hemoglobin in red blood cells found in vertebrates, hemocyanins are not confined in blood cells but are instead suspended directly in the hemolymph. Oxygenation causes a color change between the colorless Cu(I) deoxygenated form and the blue Cu(II) oxygenated form.[1]

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Protein

Protein

Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity.

Metalloprotein

Metalloprotein

Metalloprotein is a generic term for a protein that contains a metal ion cofactor. A large proportion of all proteins are part of this category. For instance, at least 1000 human proteins contain zinc-binding protein domains although there may be up to 3000 human zinc metalloproteins.

Copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement.

Oxygen

Oxygen

Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is Earth's most abundant element, and after hydrogen and helium, it is the third-most abundant element in the universe. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. Diatomic oxygen gas currently constitutes 20.95% of the Earth's atmosphere, though this has changed considerably over long periods of time. Oxygen makes up almost half of the Earth's crust in the form of oxides.

Hemoglobin

Hemoglobin

Hemoglobin, abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocytes) of almost all vertebrates as well as the tissues of some invertebrates. Hemoglobin in blood carries oxygen from the respiratory organs to the rest of the body. There it releases the oxygen to permit aerobic respiration to provide energy to power functions of an organism in the process called metabolism. A healthy individual human has 12 to 20 grams of hemoglobin in every 100 mL of blood.

Hemolymph

Hemolymph

Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph cells called hemocytes are suspended. In addition to hemocytes, the plasma also contains many chemicals. It is the major tissue type of the open circulatory system characteristic of arthropods. In addition, some non-arthropods such as mollusks possess a hemolymphatic circulatory system.

Color

Color

Color or colour is the visual perception based on the electromagnetic spectrum. Though color is not an inherent property of matter, color perception is related to an object's light absorption, reflection, emission spectra and interference. For most humans, color are perceived in the visible light spectrum with three types of cone cells (trichromacy). Other animals may have a different number of cone cell types or have eyes sensitive to different wavelength, such as bees that can distinguish ultraviolet, and thus has a different color sensitivity range. Animal perception of color originates from different light wavelength or spectral sensitivity in cone cell types, which is then processed by the brain.

Blue

Blue

Blue is one of the three primary colours in the RYB colour model, as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colours; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective.

Species distribution

Hemocyanin was first discovered in Octopus vulgaris by Leon Fredericq in 1878. The presence of copper in molluscs was detected even earlier by Bartolomeo Bizio in 1833.[2] Hemocyanins are found in the Mollusca and Arthropoda including cephalopods and crustaceans and utilized by some land arthropods such as the tarantula Eurypelma californicum,[3] the emperor scorpion,[4] and the centipede Scutigera coleoptrata. Also, larval storage proteins in many insects appear to be derived from hemocyanins.[5]

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Bartolomeo Bizio

Bartolomeo Bizio

Bartolomeo Bizio was an Italian chemist and a pioneer of microbiology who examined bloody spots on polenta and recognized them as being caused by a microorganism that he named as Serratia after the Florentine physicist Serafino Serrati.

Mollusca

Mollusca

Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks. Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied.

Cephalopod

Cephalopod

A cephalopod is any member of the molluscan class Cephalopoda such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology.

Crustacean

Crustacean

Crustaceans form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. Some crustaceans are more closely related to insects and the other hexapods than they are to certain other crustaceans.

Emperor scorpion

Emperor scorpion

The emperor scorpion, Pandinus imperator, is a species of scorpion native to rainforests and savannas in West Africa. It is one of the largest scorpions in the world and lives for 6–8 years. Its body is black, but like other scorpions it glows pastel green or blue under ultraviolet light. It is a popular species in the pet trade, and is protected by CITES to prevent over-collecting that might impact the species' survival.

Scutigera coleoptrata

Scutigera coleoptrata

Scutigera coleoptrata, also known as the house centipede, is a species of centipede that is typically yellowish-grey and has up to 15 pairs of long legs. Originating in the Mediterranean region, it has spread to other parts of the world, where it can live in human homes. It is an insectivore; it kills and eats other arthropods, such as insects and arachnids.

The hemocyanin superfamily

The arthropod hemocyanin superfamily is composed of phenoloxidases, hexamerins, pseudohemocyanins or cryptocyanins, and (dipteran) hexamerin receptors.[6]

Phenoloxidase are copper containing tyrosinases. These proteins are involved in the process of sclerotization of arthropod cuticle, in wound healing, and humoral immune defense. Phenoloxidase is synthesized by zymogens and are activated by cleaving an N-terminal peptide.[7]

Hexamerins are storage proteins commonly found in insects. These proteins are synthesized by the larval fat body and are associated with molting cycles or nutritional conditions.[8]

Pseudohemocyanin and cryptocyanins genetic sequences are closely related to hemocyanins in crustaceans. These proteins have a similar structure and function, but lack the copper binding sites.[9]

The evolutionary changes within the phylogeny of the hemocyanin superfamily are closely related to the emergence of these different proteins in various species. The understanding of proteins within this superfamily would not be well understood without the extensive studies of hemocyanin in arthropods.[10]

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Zymogen

Zymogen

In biochemistry, a zymogen, also called a proenzyme, is an inactive precursor of an enzyme. A zymogen requires a biochemical change for it to become an active enzyme. The biochemical change usually occurs in Golgi bodies, where a specific part of the precursor enzyme is cleaved in order to activate it. The inactivating piece which is cleaved off can be a peptide unit, or can be independently-folding domains comprising more than 100 residues. Although they limit the enzyme's ability, these N-terminal extensions of the enzyme or a “prosegment” often aid in the stabilization and folding of the enzyme they inhibit.

N-terminus

N-terminus

The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amine group is bonded to the carboxylic group of another amino acid, making it a chain. That leaves a free carboxylic group at one end of the peptide, called the C-terminus, and a free amine group on the other end called the N-terminus. By convention, peptide sequences are written N-terminus to C-terminus, left to right (in LTR writing systems). This correlates the translation direction to the text direction, because when a protein is translated from messenger RNA, it is created from the N-terminus to the C-terminus, as amino acids are added to the carboxyl end of the protein.

Peptide

Peptide

Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides which have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides.

Fat body

Fat body

Fat body is a highly dynamic insect tissue composed primarily of storage cells. It is distributed throughout the insect's internal body cavity; the haemocoel, in close proximity to the epidermis, digestive organs and ovaries. Its main functions are nutrient storage and metabolism, for which it is commonly compared to a combination of adipose tissue and liver in mammals. However, it may also serve a variety of other roles, such as: endocrine regulation, systemic immunity, vitellogenesis, and main site of production of antimicrobial molecules called antimicrobial peptides.

Copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement.

Structure and mechanism

Although the respiratory function of hemocyanin is similar to that of hemoglobin, there are a significant number of differences in its molecular structure and mechanism. Whereas hemoglobin carries its iron atoms in porphyrin rings (heme groups), the copper atoms of hemocyanin are bound as prosthetic groups coordinated by histidine residues. Each hemocyanin monomer holds a pair of copper(I) cations in place via interactions with the imidazole rings of six histidine residues.[11] It has been noted that species using hemocyanin for oxygen transportation include crustaceans living in cold environments with low oxygen pressure. Under these circumstances hemoglobin oxygen transportation is less efficient than hemocyanin oxygen transportation.[12] Nevertheless, there are also terrestrial arthropods using hemocyanin, notably spiders and scorpions, that live in warm climates. The molecule is conformationally stable and fully functioning at temperatures up to 90 degrees C.[13]

Most hemocyanins bind with oxygen non-cooperatively and are roughly one-fourth as efficient as hemoglobin at transporting oxygen per amount of blood. Hemoglobin binds oxygen cooperatively due to steric conformation changes in the protein complex, which increases hemoglobin's affinity for oxygen when partially oxygenated. In some hemocyanins of horseshoe crabs and some other species of arthropods, cooperative binding is observed, with Hill coefficients of 1.6–3.0. Hill coefficients vary depending on species and laboratory measurement settings. Hemoglobin, for comparison, has a Hill coefficient of usually 2.8–3.0. In these cases of cooperative binding hemocyanin was arranged in protein sub-complexes of 6 subunits (hexamer) each with one oxygen binding site; binding of oxygen on one unit in the complex would increase the affinity of the neighboring units. Each hexamer complex was arranged together to form a larger complex of dozens of hexamers. In one study, cooperative binding was found to be dependent on hexamers being arranged together in the larger complex, suggesting cooperative binding between hexamers. Hemocyanin oxygen-binding profile is also affected by dissolved salt ion levels and pH.[14]

Hemocyanin is made of many individual subunit proteins, each of which contains two copper atoms and can bind one oxygen molecule (O2). Each subunit weighs about 75 kilodaltons (kDa). Subunits may be arranged in dimers or hexamers depending on species; the dimer or hexamer complex is likewise arranged in chains or clusters with weights exceeding 1500 kDa. The subunits are usually homogeneous, or heterogeneous with two variant subunit types. Because of the large size of hemocyanin, it is usually found free-floating in the blood, unlike hemoglobin.[15]

The 3.8 MDa structure of molluscan Japanese flying squid hemocyanin. It is a homodecamer of five dimers arranged into a 31 nm diameter cylinder. Each monomer has a string of eight individual subunits each with a Cu2O2 binding site.[16] PDB: 4YD9​
The 3.8 MDa structure of molluscan Japanese flying squid hemocyanin. It is a homodecamer of five dimers arranged into a 31 nm diameter cylinder. Each monomer has a string of eight individual subunits each with a Cu2O2 binding site.[16] PDB: 4YD9

Hexamers are characteristic of arthropod hemocyanins.[17] A hemocyanin of the tarantula Eurypelma californicum[3] is made up of 4 hexamers or 24 peptide chains. A hemocyanin from the house centipede Scutigera coleoptrata[18] is made up of 6 hexamers or 36 chains. Horseshoe crabs have an 8-hexamer (i. e. 48-chain) hemocyanin. Simple hexamers are found in the spiny lobster Panulirus interruptus and the isopod Bathynomus giganteus.[17] Peptide chains in crustaceans are about 660 amino acid residues long, and in chelicerates they are about 625. In the large complexes there is a variety of variant chains, all about the same length; pure components do not usually self-assemble.

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Iron

Iron

Iron is a chemical element with symbol Fe and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, just ahead of oxygen, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust, being mainly deposited by meteorites in its metallic state, with its ores also being found there.

Porphyrin

Porphyrin

Porphyrins are a group of heterocyclic macrocycle organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (=CH−). The parent of porphyrins is porphine, a rare chemical compound of exclusively theoretical interest. Substituted porphines are called porphyrins. With a total of 26 π-electrons, of which 18 π-electrons form a planar, continuous cycle, the porphyrin ring structure is often described as aromatic. One result of the large conjugated system is that porphyrins typically absorb strongly in the visible region of the electromagnetic spectrum, i.e. they are deeply colored. The name "porphyrin" derives from the Greek word πορφύρα (porphyra), meaning purple.

Heme

Heme

Heme, or haem, is a precursor to hemoglobin, which is necessary to bind oxygen in the bloodstream. Heme is biosynthesized in both the bone marrow and the liver.

Copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement.

Prosthetic group

Prosthetic group

A prosthetic group is the non-amino acid component that is part of the structure of the heteroproteins or conjugated proteins, being tightly linked to the apoprotein.

Histidine

Histidine

Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the deprotonated –COO− form under biological conditions), and an imidazole side chain (which is partially protonated), classifying it as a positively charged amino acid at physiological pH. Initially thought essential only for infants, it has now been shown in longer-term studies to be essential for adults also. It is encoded by the codons CAU and CAC.

Imidazole

Imidazole

Imidazole (ImH) is an organic compound with the formula C3N2H4. It is a white or colourless solid that is soluble in water, producing a mildly alkaline solution. In chemistry, it is an aromatic heterocycle, classified as a diazole, and has non-adjacent nitrogen atoms in meta-substitution.

Cooperative binding

Cooperative binding

Cooperative binding occurs in molecular binding systems containing more than one type, or species, of molecule and in which one of the partners is not mono-valent and can bind more than one molecule of the other species. In general, molecular binding is an interaction between molecules that results in a stable physical association between those molecules.

Protein complex

Protein complex

A protein complex or multiprotein complex is a group of two or more associated polypeptide chains. Protein complexes are distinct from multienzyme complexes, in which multiple catalytic domains are found in a single polypeptide chain.

Horseshoe crab

Horseshoe crab

Horseshoe crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are chelicerates, most closely related to arachnids such as spiders, ticks, and scorpions.

PH

PH

In chemistry, pH, also referred to as acidity, historically denoting "potential of hydrogen", is a scale used to specify the acidity or basicity of an aqueous solution. Acidic solutions are measured to have lower pH values than basic or alkaline solutions.

Dalton (unit)

Dalton (unit)

The dalton or unified atomic mass unit is a non-SI unit of mass widely used in physics and chemistry. It is defined as 1⁄12 of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. The atomic mass constant, denoted mu, is defined identically, giving mu = m(12C)/12 = 1 Da.

Catalytic activity

A hemocyanin active site in the absence of O2 (each Cu center is a cation, charges not shown).
A hemocyanin active site in the absence of O2 (each Cu center is a cation, charges not shown).
O2-bound form of a hemocyanin active site (the Cu2 center is a dication, charge not shown).
O2-bound form of a hemocyanin active site (the Cu2 center is a dication, charge not shown).

Hemocyanin is homologous to the phenol oxidases (e.g. tyrosinase) since both proteins have histidine residues, called "type 3" copper-binding coordination centers, as do the enzymes tyrosinase and catechol oxidase.[19] In both cases inactive precursors to the enzymes (also called zymogens or proenzymes) must be activated first. This is done by removing the amino acid that blocks the entrance channel to the active site when the proenzyme is not active. There is currently no other known modifications necessary to activate the proenzyme and enable catalytic activity. Conformational differences determine the type of catalytic activity that the hemocyanin is able to perform.[20] Hemocyanin also exhibits phenol oxidase activity, but with slowed kinetics from greater steric bulk at the active site. Partial denaturation actually improves hemocyanin's phenol oxidase activity by providing greater access to the active site.[1][19]

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Tyrosinase

Tyrosinase

Tyrosinase is an oxidase that is the rate-limiting enzyme for controlling the production of melanin. The enzyme is mainly involved in two distinct reactions of melanin synthesis otherwise known as the Raper Mason pathway. Firstly, the hydroxylation of a monophenol and secondly, the conversion of an o-diphenol to the corresponding o-quinone. o-Quinone undergoes several reactions to eventually form melanin. Tyrosinase is a copper-containing enzyme present in plant and animal tissues that catalyzes the production of melanin and other pigments from tyrosine by oxidation. It is found inside melanosomes which are synthesized in the skin melanocytes. In humans, the tyrosinase enzyme is encoded by the TYR gene.

Histidine

Histidine

Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the deprotonated –COO− form under biological conditions), and an imidazole side chain (which is partially protonated), classifying it as a positively charged amino acid at physiological pH. Initially thought essential only for infants, it has now been shown in longer-term studies to be essential for adults also. It is encoded by the codons CAU and CAC.

Catechol oxidase

Catechol oxidase

Catechol oxidase is a copper oxidase that contains a type 3 di-copper cofactor and catalyzes the oxidation of ortho-diphenols into ortho-quinones coupled with the reduction of molecular oxygen to water. It is present in a variety of species of plants and fungi including Ipomoea batatas and Camellia sinensis. Metalloenzymes with type 3 copper centers are characterized by their ability to reversibly bind dioxygen at ambient conditions. In plants, catechol oxidase plays a key role in enzymatic browning by catalyzing the oxidation of catechol to o-quinone in the presence of oxygen, which can rapidly polymerize to form the melanin that grants damaged fruits their dark brown coloration.

Zymogen

Zymogen

In biochemistry, a zymogen, also called a proenzyme, is an inactive precursor of an enzyme. A zymogen requires a biochemical change for it to become an active enzyme. The biochemical change usually occurs in Golgi bodies, where a specific part of the precursor enzyme is cleaved in order to activate it. The inactivating piece which is cleaved off can be a peptide unit, or can be independently-folding domains comprising more than 100 residues. Although they limit the enzyme's ability, these N-terminal extensions of the enzyme or a “prosegment” often aid in the stabilization and folding of the enzyme they inhibit.

Conformational isomerism

Conformational isomerism

In chemistry, conformational isomerism is a form of stereoisomerism in which the isomers can be interconverted just by rotations about formally single bonds. While any two arrangements of atoms in a molecule that differ by rotation about single bonds can be referred to as different conformations, conformations that correspond to local minima on the potential energy surface are specifically called conformational isomers or conformers. Conformations that correspond to local maxima on the energy surface are the transition states between the local-minimum conformational isomers. Rotations about single bonds involve overcoming a rotational energy barrier to interconvert one conformer to another. If the energy barrier is low, there is free rotation and a sample of the compound exists as a rapidly equilibrating mixture of multiple conformers; if the energy barrier is high enough then there is restricted rotation, a molecule may exist for a relatively long time period as a stable rotational isomer or rotamer. When the time scale for interconversion is long enough for isolation of individual rotamers, the isomers are termed atropisomers. The ring-flip of substituted cyclohexanes constitutes another common form of conformational isomerism.

Spectral properties

The underside of the carapace of a red rock crab (Cancer productus). The purple coloring is caused by hemocyanin.
The underside of the carapace of a red rock crab (Cancer productus). The purple coloring is caused by hemocyanin.

Spectroscopy of oxyhemocyanin shows several salient features:[21]

  1. Resonance Raman spectroscopy shows that O2 is bound in a symmetric environment (ν(O-O) is not IR-allowed).
  2. OxyHc is EPR-silent indicating the absence of unpaired electrons
  3. Infrared spectroscopy shows ν(O-O) of 755 cm−1

Much work has been devoted to preparing synthetic analogues of the active site of hemocyanin.[21] One such model, which features a pair of copper centers bridged side-on by peroxo ligand, shows ν(O-O) at 741 cm−1 and a UV-Vis spectrum with absorbances at 349 and 551 nm. Both of these measurements agree with the experimental observations for oxyHc.[22] The Cu-Cu separation in the model complex is 3.56 Å, that of oxyhemocyanin is ca. 3.6 Å (deoxyHc: ca. 4.6 Å).[22][23][24]

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Cancer productus

Cancer productus

Cancer productus, one of several species known as red rock crabs, is a crab of the genus Cancer found on the western coast of North America. This species is commonly nicknamed the Pearl of the Pacific Northwest.

Raman spectroscopy

Raman spectroscopy

Raman spectroscopy is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. Raman spectroscopy is commonly used in chemistry to provide a structural fingerprint by which molecules can be identified.

Electron paramagnetic resonance

Electron paramagnetic resonance

Electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is a method for studying materials that have unpaired electrons. The basic concepts of EPR are analogous to those of nuclear magnetic resonance (NMR), but the spins excited are those of the electrons instead of the atomic nuclei. EPR spectroscopy is particularly useful for studying metal complexes and organic radicals. EPR was first observed in Kazan State University by Soviet physicist Yevgeny Zavoisky in 1944, and was developed independently at the same time by Brebis Bleaney at the University of Oxford.

Infrared spectroscopy

Infrared spectroscopy

Infrared spectroscopy is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functional groups in solid, liquid, or gaseous forms. It can be used to characterize new materials or identify and verify known and unknown samples. The method or technique of infrared spectroscopy is conducted with an instrument called an infrared spectrometer which produces an infrared spectrum. An IR spectrum can be visualized in a graph of infrared light absorbance on the vertical axis vs. frequency, wavenumber or wavelength on the horizontal axis. Typical units of wavenumber used in IR spectra are reciprocal centimeters, with the symbol cm−1. Units of IR wavelength are commonly given in micrometers, symbol μm, which are related to the wavenumber in a reciprocal way. A common laboratory instrument that uses this technique is a Fourier transform infrared (FTIR) spectrometer. Two-dimensional IR is also possible as discussed below.

Anticancer effects

The hemocyanin found in the blood of the Chilean abalone, Concholepas concholepas, has immunotherapeutic effects against bladder cancer in murine models. Mice primed with C. concholepas before implantation of bladder tumor (MBT-2) cells. Mice treated with C. concholepas hemocyanin showed antitumor effects: prolonged survival, decreased tumor growth and incidence, and lack of toxic effects and may have a potential use in future immunotherapy for superficial bladder cancer.[25]

Keyhole limpet hemocyanin (KLH) is an immune stimulant derived from circulating glycoproteins of the marine mollusk Megathura crenulata. KLH has been shown to be a significant treatment against the proliferations of breast cancer, pancreas cancer, and prostate cancer cells when delivered in vitro. Keyhole limpet hemocyanin inhibits growth of human Barrett's esophageal cancer through both apoptic and nonapoptic mechanisms of cell death.[26]

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Case studies: environmental impact on hemocyanin levels

A 2003 study of the effect of culture conditions of blood metabolites and hemocyanin of the white shrimp Litopenaeus vannamei found that the levels of hemocyanin, oxyhemocyanin in particular, are affected by the diet. The study compared oxyhemocyanin levels in the blood of white shrimp housed in an indoor pond with a commercial diet with that of white shrimp housed in an outdoor pond with a more readily available protein source (natural live food) as well. Oxyhemocyanin and blood glucose levels were higher in shrimp housed in outdoor ponds. It was also found that blood metabolite levels tended to be lower in low activity level species, such as crabs, lobsters, and the indoor shrimp when compared to the outdoor shrimp. This correlation is possibly indicative of the morphological and physiological evolution of crustaceans. The levels of these blood proteins and metabolites appear to be dependent on energetic demands and availability of those energy sources.[27]

Source: "Hemocyanin", Wikipedia, Wikimedia Foundation, (2023, March 19th), https://en.wikipedia.org/wiki/Hemocyanin.

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References
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