期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：2001
卷号：47
期号：4
页码：275-282
DOI：10.3177/jnsv.47.275
出版社：Center for Academic Publications Japan
摘要：β-Alanine-oxoglutarate aminotransferase (β-AIaAT I) and β-alanine-pyru-vate aminotransferase (β-AlaAT II) catalyze the transamination reaction of ω-amino acids such as β-alanine, β-aminoisobutyrate, and γ-aminobutyrate, amino acids that are not pro-tein constituents. The influence of dietary protein levels on the expression and activities of these enzymes was investigated by using male rats. Both, β-AIaAT I and β-AIaAT II activities in the liver were increased with the level of protein in the diet in accordance with changes in their mRNA levels. However, the β-AlaAT I activity in the kidney was increased by protein-free and low-protein diets in relation to changes in its mRNA level. On the other hand, the level of β-AIaAT II activity in the kidney was slightly decreased by a protein-free diet. Neither β-AIaAT I nor β-AIaAT II activities in the kidney were affected by a high-protein diet. These results suggested that β-alanine may be used efficiently in animals fed a protein-free or low-protein diet because the kidney provides β-alanine by means of the hydrolysis of β-alanyl-L-histidine (carnosine). The addition of, β-alanine to the diet significantly activatedβ-AIaAT I in the kidneys of rats in accordance with changes in its mRNA level. In the rat brain, β-AIaAT I activity was not altered by the dietary protein level or by the β-alanine diet, and β-AIaAT II activity was not detected.
