| Autor: |
Albanese, Anthony A., Holt, L. Emmett, Brum-Back, Joseph E., Hayes, Marjorie, Kajdi, Charlotte, Wangerin, Dorothy M. |
| Zdroj: |
Experimental Biology and Medicine; December 1941, Vol. 48 Issue: 3 p728-730, 3p |
| Abstrakt: |
As part of a general study designed to determine the amino acids essential for man, the nitrogen balance was studied in 5 human volunteers who were given a diet deficient in lysine for periods of 2 to 5 weeks in length. The basic diet and the conditions of the experiment were similar to those outlined in the accompanying report1on tryptophane deficiency. The amino acid mixture deficient in lysine was prepared by deamination of casein, a process which has been shown to destroy the biological activity of lysine;2this was followed by acid hydrolysis, with the addition of 1.5% tryptophane (to replace that lost during hydrolysis) and of 1% cystine.Before the deficient diet was instituted the subjects were given a diet identical with the experimental diet except that an amino acid mixture containing lysine was supplied. This mixture consisted of an enzymatic hydrolysate of casein, enriched by 1% cystine. A control period on an amino acid mixture containing lysine followed the deficiency period. In subjects Es. and Ha. the amino acid mixture in the control period was identical with that of the experimental period except that 6% lysine was added. In subjects Ra., He. and Hs., the amino acid mixture in the control period was identical with that used in the foreperiod.The observations on nitrogen balance in 4 male subjects are shown in Fig. 1. It may be seen that each subject developed a negative nitrogen balance within a few days after the lysine-deficient diet was started, and that nitrogen equilibrium was promptly restored when lysine was again supplied. The failure to maintain nitrogen equilibrium in the absence of an adequate supply of this amino acid indicates clearly that lysine is a dietary essential for the human subject. |
| Databáze: |
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