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

We investigated the mechanism by which the three most commonly measured enzymes in erythrocytes are activated by their respective coenzymes by determining the catalytic activity concentrations of transketolase (EC 2.2.1.1), aspartate aminotransferase (EC 2.6.1.1), and glutathione reductase (EC 1.6.4.2) in relation to various substrate concentrations. We conclude that the underlying mechanisms by which the enzymes are activated are not the same.
 ...
PMID:Influence of substrate concentration on the activation of transketolase, aspartate aminotransferase, and glutathione reductase by coenzymes. 669 Jan 23

One hundred and seventy-two successive admissions to a district general hospital psychiatric unit were examined. Routine psychiatric, drug and dietary histories were taken and signs of avitaminosis B specifically noted. Red cell transketolase (for thiamine deficiency), glutathione reductase (for riboflavin deficiency) and aspartate transaminase (for pyridoxine deficiency) were measured. Of the patients, 53 per cent were deficient in at least one vitamin, 12 per cent in more than one (30 per cent in thiamine, 27 per cent in riboflavin and 9 per cent in pyridoxine). Schizophrenics and alcoholics were significantly over-represent in those patients low in thiamine and in more than one vitamin. Patients with an affective disorder had low riboflavin and low pyridoxine. It is suggested that affective changes are characteristic of riboflavin and pyridoxine deficiency.
 ...
PMID:Thiamine, riboflavin and pyridoxine deficiency in psychiatric in-patients. 713 10

The effects of simultaneous administration of thiamine, niacin or vitamin B12 with vitamin E on plasma vitamin E levels were studied in 20 adult male volunteers belonging to the low socio-economic class. The effect of vitamin E on the nutritional status of pyridoxine, riboflavin and thiamine as judged by the erythrocyte enzymes, aspartate aminotransferase, glutathione reductase and transketolase, respectively was also studied. None of the members of the B-complex vitamins studied here had any effect on plasma vitamin E levels. This was in contrast to the observation made earlier that pyridoxine and riboflavin can reduce plasma vitamin E. There was a transient reduction in both the basal and stimulated activities of erythrocyte aspartate aminotransferase, the significance of which needs further investigation.
 ...
PMID:Studies on interactions of vitamin E with thiamine, niacin and vitamin B12. 731 77

By means of a 5-week vitamin B-complex supplementation, associations between indices of vitamin B1, B2, and B6 status (activation coefficients [AC] for erythrocyte transketolase, glutathione reductase, and aspartate aminotransferase) and exercise-induced blood lactate concentration were studied. Subjects, 42 physically active college students (18-32 yrs), were randomized into vitamin (n = 22) and placebo (n = 20) groups. Before the supplementation there were no differences in ACs or basal enzyme activities between the groups. The ACs were relatively high, suggesting marginal vitamin status. In the vitamin group, all three ACs were lower (p < 0.0001) after supplementation: transketolase decreased from 1.16 (1.14-1.18) (mean and 95% confidence interval) to 1.08 (1.06-1.10); glutathione reductase decreased from 1.33 (1.28-1.39) to 1.14 (1.11-1.17); and aspartate aminotransferase decreased from 2.04 (1.94-2.14) to 1.73 (1.67-1.80). No changes were found after placebo. Despite improved indices of vitamin status, supplementation did not affect exercise-induced blood lactate concentration. Hence no association was found between ACs and blood lactate. It seems that marginally high ACs do not necessarily predict altered lactate metabolism.
 ...
PMID:Lack of association between indices of vitamin B1, B2, and B6 status and exercise-induced blood lactate in young adults. 850 94

RNA, DNA, total protein, transketolase (TK), alanine aminotransferase (AlAT), aspartate aminotransferase (AsAT), methionyl-tRNA (met-tRNA)- and cysteinyl-tRNA (cys-tRNA)-synthetases in the thymus and spleen of 46 intact rats exposed to hypokinesia and vitamin B1 deficiency were measured. It was found that 15-day hypokinesia induced a significant decrease of the thymus and spleen weight and an increase of AlAT in the thymus. Vitamin B1 deficiency (hydroxy thiamine in drinking water at a dose of 2 mg/kg body weight for 15 days) led to a substantial decrease of TK in blood, AlAT and AsAT in the spleen; it diminished AsAT and increased AlAT in the thymus. Combined exposure to hypokinesia and vitamin B1 deficiency caused a more marked decrease of the weight of lymph organs, a significant loss of body weight, an increase of DNA in the thymus and spleen, and an increase of TK, met-tRNA-synthetase and AlAT in the thymus. These results suggest that vitamin B1 deficiency aggravates disorders in protein and nucleic acid metabolism in the lymph organs of hypokinetic animals.
 ...
PMID:[Several indicators of protein and nucleic acid metabolism in lymphoid organs of rats exposed to hypokinesia and vitamin B1 deficiency]. 857 40

One thousand and seven hundred thirty-six school children from two districts in Nakhon Si Thammarat Province were screened for hookworm infection using the Kato-Katz stool examination technic. Two hundred students who have at least 2,000 eggs per g of stool were recruited into the program. The students were divided into six groups: groups 1, 2 and 3 were from Tha Sala district while groups 4, 5 and 6 were from Ronpibul district. Three milliliter blood samples were obtained from the cubital vein of each subject and were evaluated for erythrocyte transketolase activity (ETK) for vitamin B1, erythrocyte glutathione oxidoreductase activity (EGR) for vitamin B2, and erythrocyte aspartate aminotransferase activity (EAST) for vitamin B6. The school children were divided into three groups: those infected only with hookworm, those with both hookworm and Trichuris trichiura, and those whose stools show no parasite eggs. The results show that 10-20% of the school children are vitamin B1 deficient, about 40% to 80% are vitamin B2 deficient, and about 14% to 23% are vitamin B6 deficient. No correlation could be made between vitamin deficiencies and parasitic infection.
 ...
PMID:Vitamin B1, B2 and B6 deficiency in primary school children infected with hookworm. 903 99

Some patients with chronic fatigue syndrome say they benefit from taking vitamin supplements. We assessed functional status for the B vitamins pyridoxine, riboflavin and thiamine in 12 vitamin-untreated CFS patients and in 18 healthy controls matched for age and sex. Vitamin-dependent activities--aspartate aminotransferase (AST) for pyridoxine, glutathione reductase (GTR) for riboflavin, transketolase (TK) for thiamine--were measured in erythrocyte haemolysates before and after in-vitro addition of the relevant vitamin. For all three enzymes basal activity (U/g Hb) was lower in CFS patients than in controls: AST 2.84 (SD 0.62) vs 4.61 (1.43), P < 0.001; GTR 6.13 (1.89) vs 7.42 (1.25), P < 0.04; TK 0.50 (0.13) vs 0.60 (0.07), P < 0.04. This was also true of activated values: AST 4.91 (0.54) vs 7.89 (2.11), P < 0.001; GTR 8.29 (1.60) vs 10.0 (1.80), P < 0.001; TK 0.56 (0.19) vs 0.66 (0.08), P < 0.07. The activation ratios, however, did not differ between the groups. These data provide preliminary evidence of reduced functional B vitamin status, particularly of pyridoxine, in CFS patients.
 ...
PMID:Vitamin B status in patients with chronic fatigue syndrome. 1045 Jan 94

The aim of this study was to assess the prevalence of thiamin, riboflavin and pyridoxine deficiencies at admission to an acute hospital. One hundred and twenty adult patients were selected at random from those admitted via the Accident and Emergency department over 3 days. Comparisons were made with a group of 80 healthy blood donors sequentially attending a local transfusion centre. The alcohol intake of 500 patients admitted sequentially via the same Accident and Emergency department was also assessed. Erythrocyte transketolase (ETK), glutathione reductase (EGR) and aspartate aminotransferase (EAA) coenzyme activation assays were used to determine thiamin, riboflavin and pyridoxine deficiencies. The prevalences of deficiency states in the inpatient group were 21, 2.7 and 32% for thiamin, riboflavin and pyridoxine deficiencies respectively with 49.2% being deficient in one or more vitamin. The mean alcohol intake in the group of patients in whom this was assessed was 9.7 units per week compared with 10 units per week amongst blood donors.
 ...
PMID:The thiamin, riboflavin and pyridoxine status of patients on emergency admission to hospital. 1045 67

Chronic alcoholism and thiamine deficiency are well documented factors in the aetiology of Wernicke-Korsakoff Syndrome. More recently, acetaldehyde (ACH) has been implicated as a possible aetiological factor. In the present investigation the direct effect of ACH was studied on the activity of transketolase, a thiaminedependent enzyme, as well as two non-thiamine-dependent enzymes (aspartate aminotransferase and lactate dehydrogenase), isolated from five control human brains. The concentration of ACH required to inhibit 50% activity of holo- and apo-transketolase was 80 mM and 60 mM, respectively, whereas that for aspartate aminotransferase and lactate dehydrogenase was 14 mM and 10 mM, respectively. None of the enzymes were completely inhibited by the range of ACH concentrations used in the study. It was concluded that the thiamineindependent enzymes were markedly affected by the concentrations of ACH which did not affect the thiaminedependent enzyme, transketolase. In vitro studies with homogenates pre-treated with ACH in the presence of various concentrations of glutathione showed that the latter had a protective effect against loss of transketolase activity.
...
PMID:The effect of acetaldehyde on human brain transketolase activity. 2673 91

The history and applications of food irradiation are reviewed. The term wholesomeness when applied to food irradiation, embodies the concepts of microbiological and toxicological safety, and nutritional adequacy. The status of these areas of concern is reviewed. Nutritional studies have addressed the effects of irradiation on nutrient content and bioavailability, and evaluation of potential consequences of changes in either. Results of rat studies are presented in which we tested for the presence of anti-thiamin and anti-pyridoxine activity in radappertized chicken and beef. Test meats were analyzed for thiamin and pyridoxine to establish a basis for incorporation into repletion diets. Thiamin levels in gamma- and electron-irradiated, and thermally processed (commercial canning) chicken were 74, 34 and 78%, respectively, of the vitamin level in a frozen meat reference; the levels in beef were 77, 56 and 79%, respectively. Pyridoxine levels in chicken were 50, 38 and 17%, respectively, of the reference level. Rats were depleted in each vitamin, then repleted at two vitamin levels with diets containing test meats. Activities of transketolase, aspartate aminotransferase and alanine aminotransferase in erythrocytes from these rats provided no consistent evidence of antivitamin presence. It was concluded that these irradiated meats pose no problem regarding vitamins B1 and B6 if part of a complete diet.
 ...
PMID:Wholesomeness of Irradiated Foods. 3096 1


<< Previous 1 2