. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 378 JOHN W. SIMPSON, KENNETH ALLEN AND JORGE AWAPARA to hypotaurine (Awapara and Wingo, 1953). Hypotaurine is then oxidized to taurine. Hypotaurine has been reported only once in invertebrates (Shibuya and Ouchi, 1957). The cysteine sulrmic decarboxylase has not been reported in invertebrates. There is the possibility that taurine is not produced by inverte- brates but acquired from their diet. Glycine, which is also present in very high amounts, could also be obtained from their diet. One objection to this possibil- ity is
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 378 JOHN W. SIMPSON, KENNETH ALLEN AND JORGE AWAPARA to hypotaurine (Awapara and Wingo, 1953). Hypotaurine is then oxidized to taurine. Hypotaurine has been reported only once in invertebrates (Shibuya and Ouchi, 1957). The cysteine sulrmic decarboxylase has not been reported in invertebrates. There is the possibility that taurine is not produced by inverte- brates but acquired from their diet. Glycine, which is also present in very high amounts, could also be obtained from their diet. One objection to this possibil- ity is the wide range of variation in the taurine concentration of species from the same environment. Aspartic acid, glutamic acid, and alanine vary much less in concentration than taurine and three amino acids are closely linked to the citric acid. 55 Alanine HI Arginine l^i Aspartic Glycine •X;X;X Glutamic •III Taurine LITHOPHAGA LOLIGUNCULA FIGURE 5. Estimated concentration of six amino acids in the tissues of pelecypods Lithophage bisulcata and the cephalopod LoUguncnla brcvis. cycle and their concentration could be easily regulated by the reactions of the cycle. /?-alanine was found in some forms but not in others. The only coelenterate which we studied had none. It was found in some Mollusca but not in others. The same was true in the arthropods studied. The function of /?-alanine is again unknown. It exists usually as a moiety of carnosine which is known to exist in the muscle of vertebrates and many invertebrates. The problem of formation arises again, /?- alanine can be produced by the decarboxylation of aspartic acid, or by the hydrolytic breakdown of dihydrouracil. Similarly, /?-ammoisobutyric acid is formed by the hydrolytic breakdown of dihydrothymine. We found /?-aminoisobutyric acid in. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustra
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