Peptide species specificity

Alternatively, species-specific peptides can be targeted and partially sequenced to confirm the presence or absence of microorganisms of high interest. 

Proteins are polymers of amino acids linked together by peptide bonds the same family of 20 amino acids is employed by all living organisms to construct their proteins. The sequence of amino acids along the chain defines the primary structure of the protein, a species-specific quality. 

Polatajko, A., Encinar, J. R., Schaumloffel, D., and Szpunar, J., Quantification of a selenium-containing protein in yeast extract via an accurate determination of a tryptic peptide by species-specific isotope dilution capillary HPLC-ICP MS, Chemia Analityczna 50(1), 265-278, 2005. 

Insulin therefore consists of two peptide chains that are connected by two disulfide bonds, since the C-peptide is cleaved off. There are some species-specific differences in the amino acid sequence of the hormone. X-ray diffraction studies have shown that insulin occurs as a hexameric protein containing two Zn atoms. The dimers are first held by four hydrogen bonds and a hydrophobic bond along the sequence in the form of an antiparallel P sheet. The dimers then bind by interaction of the B -Ala, B -Leu, and B -Val residues. The core of the hexamer contains water. 

Both the human and the murine IFN-y receptors consist of a ligand-binding subunit and a species-specific cofactor molecule. It is through interaction with this cell-surface receptor complex that IFN-y exerts its biological effects. The IFN-y molecule and its N-terminal peptide IFN-y (1-39) bind specifically to the... 

Banks, W.A., J.B. Jaspan, and A.J. Kastin. 1997. Selective, physiological transport of insulin across the blood-brain barrier Novel demonstration by species-specific radioimmunoassays. Peptides 18 1257. 

Human ACTH is a single peptide chain of 39 amino acids. The amino terminal portion containing amino acids 1-24 is necessary for full biologic activity. The remaining amino acids (25-39) confer species specificity. Synthetic human ACTHi 24 is known as cosyntropin. The amino terminal amino acids 1-13 are identical to melanocyte-stimulating hormone (cr-MSH), which has been found in animals but not in humans. In states of excessive pituitary ACTH secretion (Addison s disease or an ACTH-secreting pituitary tumor), hyperpigmentation—caused by the -MSH activity intrinsic to ACTH—may be noted. 

Peptides and proteins exhibit distinct species specificity with regard to structure and activity. Peptides and proteins with identical physiological function may have different amino acid sequences in different species, and may have no activity or be even immunogenic if used in a different species. 

FIGURE 1 Proteomics pipeline used for the identification, characterization, and detection of species-specific peptide biomarkers for fish authentication purposes. 

Kontureketal. (1976,1984) performed experiments with chronic gastric fistulas in cats as well as in dogs to compare the species-specific activities of vasoactive intestinal peptide and secretin in stimulation of pancreatic secretion. 

Mating in most species of moths is mediated through the production and release of species-specific sex pheromones by the females and, in a majority of the moths, reproductive activity is limited to the hours of darkness. To achieve this diurnal periodicity of mating, production of sex pheromone must also be synchronized (JL). In the corn earworm, Helicoverpa Heliothls) zea, and in many other species of moths, this synchronization is affected by a factor produced in the head of the female (2.). The factor was identified as a peptide hormone, produced in the suboesophageal ganglion (SOG) and most likely... 

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