Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Of 150 patients undergoing regular hemodialysis (HD), 14 (9.3%) and 12 (8.0%), respectively, showed low serum activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). An investigation was conducted to elucidate the underlying mechanisms in 20 patients with low serum AST and/or ALT activity. Fifty-five percent of the patients with low aminotransferase activity manifested serum levels of pyridoxal phosphate (PLP) that were lower than normal. Serum PLP levels correlated neither with AST nor with ALT activity. Oral administration of vitamin B6 to the cases with low aminotransferase activity resulted in an increase in pre-hemodialysis aminotransferase activity. Addition of vitamin B6 in vitro to the sera from the patients with low aminotransferase activity did not increase the values when the added vitamin B6 was within the physiological range, but did increase when added in larger (pharmacological) amounts. However, aminotransferase activity increased, but PLP levels remained unchanged when these values were compared before and after HD. On the other hand, guanase being within the normal range in all cases studied, did not change after HD. Although our study does not correlate with vitamin B6 deficiency, but rather with some uremic substance(s) which interfere(s) with the enzyme reaction as a cause of low aminotransferase activity, the fact that less than 10% of our patients showed low AST and/or ALT points to the latter possibility, suggesting the need of further study.
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PMID:Low serum aminotransferase activity in patients undergoing regular hemodialysis. 802 12

Studies have indicated that vitamin B6 status decreases with age. However, little is known about vitamin B6 status of elderly people in Taiwan. The purpose of this study was to assess vitamin B6 status of elderly Taiwanese and to examine the effect of protein on various indices of vitamin B6 status in the elderly. Thirty-nine men (mean age = 69.9 +/- 4.2 years) and 55 women (mean age = 69.5 +/- 3.9 years) completed a 24-h diet recall. The mean total vitamin B6 intake (men: 1.7 +/- 0.9 g/day; women: 1.6 +/- 1.2 g/day) was higher than the 1998 US Dietary Reference Intakes (DRI) and the current Taiwan Recommended Daily Nutrient Allowance (RDNA). Dietary energy and protein intakes were not related to any vitamin B6 status parameters in any sex groups and the pooled group. Vitamin B6 intake correlated only with erythrocyte aspartate transaminase activity coefficient (EAST-AC) in the pooled (r = -0.214, p < 0.05) group. There were no significant differences in plasma pyridoxal 5'-phosphate (PLP), erythrocyte alanine transaminase activity coefficient (EALT-AC), and EAST-AC between sex groups. Although elderly subjects had adequate mean plasma PLP concentrations, 59% of men and 55% of women had plasma PLP concentrations lower than a cutoff of 20 nmol/L. The mean EALT-AC was < 1.25 in two groups with adequate vitamin B6 status. However, 23% of men and 18% of women had EALT-AC values > 1.25. The mean EAST-AC value of subjects was higher than the suggested value (< 1.8) for inadequate vitamin B6 status. The incidence of biochemical vitamin B6 deficiency in our elderly is probably more relevant from other causes than from dietary intake of protein and vitamin B6.
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PMID:Vitamin B6 intakes and status assessment of elderly men and women in Taiwan. 1172 97

The mechanism of pellagrous changes in skin caused by a deficiency of vitamin B6 was studied in respect to neogenesis of proline in skin collagen and glucose metabolism. In vitamin B6 deficiency the insulin/glucagon coefficient in serum decreased significantly from 3.02 to 2.32, indicating a metabolic change towards gluconeogenesis. A deficiency of vitamin B6 caused a decrease in the levels of vitamin B6-dependent enzymes, such as ornithine aminotransferase, alanine aminotransferase, and aspartate aminotransferase, which also contribute to gluconeogenesis. Because the conversion of ornithine to proline via pyrroline-5-carboxylate was suppressed due to the decrease in ornithine aminotransferase activity, the amount of proline in the skin collagen fraction also decreased significantly in vitamin B6-deficient rats compared with the pair-fed control. These results suggest that the pellagrous lesions in vitamin B6-deficiency are caused by an impaired synthesis of proline from ornithine, which results in the suppression of collagen neogenesis in the skin.
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PMID:Changes of glucose metabolism and skin-collagen neogenesis in vitamin B6 deficiency. 1617 47


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