| 释义 |
tryptophan Chem.|ˈtrɪptəʊfæn|
Also tryptophane.
[a. G. tryptophan (R. Neumeister 1890, in Zeitschr. f. Biol. XXVI. 3), f. tryptic a. + Gr. ϕαίνειν to appear.]
a. An amino-acid essential in the diet of vertebrates; β-3-indolylalanine, (C8H6N)CH2CH(NH2)COOH.
1890Jrnl. Chem. Soc. LVIII. 804 The term tryptophan is suggested for the substance which is formed during pancreatic digestion from proteïds, and which gives a reddish-violet coloration with bromine. 1922Sci. Amer. July 42/3 Certain of the amino acids, of which about 19 have been found in proteins, are absolutely essential for growth and maintenance, among which are lysine, cystine and tryptophane. 1945,1949[see co-factor 2]. 1956Nature 3 Mar. 422/2 Supplementation of the [rats'] diet with either nicotinic acid or tryptophan had no effect on this depressed growth-rate. 1978Detroit Free Press 5 Mar. (Parade Suppl.) 13 (Advt.), Pay less for more protein potency! A whole and complete protein derived from soybean. 0% carbohydrates, 325 mg tryptophane, 26 grams protein with lecithin and papain. 1979Time 2 Apr. 42/2 Only a small dose of tryptophan—which is found in many foods, notably milk—seems to ease the insomniac to sleep.
b. Special Comb.: tryptophan synthetase, a bacterial enzyme that synthesizes tryptophan.
1955C. Yanofsky in Colowick & Kaplan Methods in Enzymol. II. i. 233 Tryptophan synthetase from Neurospora... This enzyme has also been called tryptophan desmolase... The name tryptophan synthetase was suggested by the editors of this volume. 1976Ann. Rev. Microbiol. XXX. 413 Where this has been specifically tested—with tryptophan synthetase subunits in Escherichia coli..homologies have not been found.
Hence ˈtryptophanase [a. Jap. tryptophanase (K. Kurono et al. 1932, in Jrnl. Agric. Chem. Soc. Japan VIII. 82): see -ase], an enzyme catalysing the breakdown of tryptophan into ammonia, indole, and pyruvic acid.
1932Chem. Abstr. XXVI. 5107 (heading) Tryptophan-decomposing enzyme, tryptophanase. 1963Lancet 19 Jan. 128/1 Glucose reduces indole formation by inhibiting tryptophanase synthesis.., but does not affect the activity of tryptophanase already present. 1976Ann. Rev. Microbiol. XXX. 421 Tryptophanase from Escherichia coli can catalyze the reversal of its normal function, forming l-tryptophan from indole, pyruvate, and ammonia. |