Practical physiological chemistry : a book designed for use in courses in practical physiological chemistry in schools of medicine and of science . of any proteidsubstance. Crystals of glutamic acid, obtained from the pro-teid gliadin, are reproduced in Fig. 26. Glycocoll, C2H5N02.—Glycocoll, or amino acetic acid, isthe simplest of the amino acids and has the followingformula: NH2 H-C-COOH. H It was the second of the decomposition products of proteids tobe discovered, being preceded only by leucin. In distinctionfrom the greater number of the amino acids, glycocoll may bedetermined quantitativ
Practical physiological chemistry : a book designed for use in courses in practical physiological chemistry in schools of medicine and of science . of any proteidsubstance. Crystals of glutamic acid, obtained from the pro-teid gliadin, are reproduced in Fig. 26. Glycocoll, C2H5N02.—Glycocoll, or amino acetic acid, isthe simplest of the amino acids and has the followingformula: NH2 H-C-COOH. H It was the second of the decomposition products of proteids tobe discovered, being preceded only by leucin. In distinctionfrom the greater number of the amino acids, glycocoll may bedetermined quantitatively very accurately. Hippuric acid maybe formed synthetically through a union of glycocoll and ben- 72 PHYSIOLOGICAL CHEMISTRY, zoic acid (see page 263). This method is not used very exten-sively at present, however, having been replaced by Fischersmethod. Glycocoll, ingested in small amount, is excreted inthe urine as urea, whereas if administered in excess it appearsin part unchanged in the urine. The crystalline form of gly-cocoll ester hydrochloride, resulting from the decompositionof the proteid glutenin, is shown in Fig. 27. Fig. Glycocoll Ester Hydrochloride. Alanin, C3H7N02.—From a chemical view-point this de-composition product is a-amino-propionic acid, and as such itmay be represented structurally as follows: H NH, H-C-C-COOH. I IH H Obtained from proteid substances, alanin is dextrorotatory, isvery easily soluble in water, and possesses a sweet , phenylalanin, cystin and serin are derivatives ofalanin. DFXOMPOSITION PRODUCTS OF PROTEIDS. 73 Phenylalanin, C9HnN02.—This product is phenyl a amino-propionic acid, and may be represented graphically as follows: H NH2 I I(< C-COOH. •. Un H Phenylalanin is not so soluble as alanin, and possesses a sweettaste. The yield of this body from the decomposition of pro-teids is frequently greater than the yield of tyrosin. Thecrystalline form of phenylalanin obtained from the proteidgliadin is shown in
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