Some Naturally Occurring Peptides

The first peptide, isolated from beef extract as early as 1900 by Gulevitch and Amiradzibi, carnosine, has the formula of j -alanyl-L-histidine (Fig. 8) it was synthesized by Barger and Tutin in 1918. Anserine, the 1-methyl-histidine analog was first isolated from goose muscle in 1929 by Ackermann et al., and synthesized by Behrens and du Vigneaud in 1937. No specific physiological function could have been ascribed to these abnormal dipeptides at that time. 

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Proteins can be very long polypeptide chains of 100 to several thousand amino acid residues. However, some naturally occurring peptides have only a few amino acid residues. Some proteins are composed of several noncovalently... 

Vasopressin regulates the excretion of water by the kidneys, as noted in the A Word about Some Naturally Occurring Peptides (on page 503). 

Some naturally occurring peptides, as we have said previously, contain certain uncommon amino acids. It should be noted here that the... 

In lUPAC names, the carboxylic acid group takes precedence over amino groups. Therefore, C-1 is the carboxyl group, the parent compound is propanoic acid, and the name is therefore 3-aminopropanoic acid. Its common name is (i-alanine, which is a component of pantothenic acid (vitamin B5) and some naturally occurring peptides. 

Analogues in which one or more of the naturally occurring peptide bonds in a substrate, effector, or ligand has been replaced by some other chemical structure. Such compounds are useful in characterizing binding specificity (particularly conformational specificity), and... 

Since that time a very considerable number of small peptides containing 7-glutamyl linkages have been reported. Some of those found very recently are included in Table III, together with those mentioned above. The recent papers refer to some naturally occurring 7-glutamyl peptides which had been found previously, and these are also reported by Wald-schmidt-Leitz and Reicheneder (1961), and Franzblau (1962). 

Intensive studies on the synthesis of amanita peptides, both total and partial via chemical modification, resulted in the preparation of some naturally occurring alkaloids, such as phalloin (775) and prophalloin (776)... 

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