Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe a fully automated method for the assessment of vitamin B1, B2 and B6 status using a centrifugal analyser. The activation of the red cell enzymes transketolase, glutathione reductase and aspartate aminotransferase) by their respective coenzymes were measured in freshly prepared haemolysate. The enzyme catalytic activities in the sample were measured with (maximal activity) and without (basal activity) the coenzyme, and the percentage activation was calculated. The between run precision for red cell transketolase, glutathione reductase and aspartate aminotransferase were 8.5%, 10.3% and 9.5% respectively. When whole blood was stored at room temperature for 6 hours, red cell aspartate aminotransferase activity significantly decreased (n = 10, p less than 0.05). There were no significant changes in the activities of the other two enzymes. For a group of 30 healthy young subjects, the mean (standard deviation) values for the percentage activation of transketolase, glutathione reductase and aspartate aminotransferase were 11.9% (7.3), 35.1% (19.1) and 85.3% (18.0), respectively. The vitamin status of a group of 86 pregnant women was assessed by this method; 2.3%, 8.1% and 8.1%, respectively, of the pregnant women showed a higher percentage activation for transketolase, glutathione reductase and aspartate aminotransferase than that found in the young subjects. Both groups correlated well with respect to the basal activity and the percentage activation of each enzyme. Basal activity was inversely proportional to the percentage activation. It is therefore suggested that the basal activity can be used as a second criterion in the assessment of vitamin status.
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PMID:Assessment of vitamin B1, B2 and B6 status by coenzyme activation of red cell enzymes using a centrifugal analyser. 340 87

The relationship between riboflavin and pyridoxine status was studied in 40 patients with sickle cell disease (SCD) and 12 normal children by measuring activation coefficients of erythrocyte glutathione reductase (EGRAC) and aspartate transaminase (ASTAC). Prevalence of riboflavin deficiency was significantly lower in SCD (42.5%) than in control subjects (83%) and there was less pyridoxine deficiency in SCD (10.3%) than control subjects (54.5%). Aspartate transaminase (AST) activities in SCD patients were double those in control subjects. Pyridoxine status of patients, but not of control subjects, was directly affected by riboflavin status as judged from significant correlations between EGRAC and both AST activity and ASTAC. Poor riboflavin status in patients may be restricting availability of pyridoxal phosphate (PLP) due to combined effects of enhanced PLP requirements and effects of poor riboflavin status on the synthesis of PLP by pyridoxine phosphate oxidase (PPO). PPO activity was no different in the two groups.
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PMID:Dependence of pyridoxine metabolism on riboflavin status in sickle cell patients. 360 73

Riboflavin and vitamin B6 status of low-income mothers in Hyderabad, India, were assessed by erythrocyte glutathione reductase activation and erythrocyte aspartate aminotransferase activation tests, respectively, at different stages of lactation. Levels of these vitamins in milk also were measured. The 134 lactating women, who attended a maternal and child care clinic in a government hospital, were divided according to the duration of lactation into the following 6 groups: less than 5 days (Group I), 6-30 days (Group II), 1-6 months (Group III), 7-12 months (Group IV), 13-18 months (Group V), and more than 18 months (Group VI). 6 women had been using oral contraceptives (OCs) for 3-6 months (Group VII). Since OCs are not prescribed before 8 months of lactation, the lactational status of the OC users was comparable to that of the women in groups IV or V. Except for the pariurient mothers (Group I) who delivered in the hospital, the remainder of the women came to the hospital for routine pediatric care or contraceptive advice. Most women had had a frugal breakfast and had nursed their infants 2 hours prior to the sampling of blood and milk. 10 ml samples of foremilk (5 ml from each breast) were collected by manual expression. Samples of venous blood were draw after collecting the milk. Correlations between the maternal vitamin status and milk vitamin concentration were assessed by Pearson's correlation coefficient and frequency distribution. The majority of the women had biochemical evidence of riboflavin and pyridoxine deficiency, the incidence of the former being greater than the latter. Prolonged lactation did not worsen the vitamin status. Group II women showed a reduction in erythrocyte glutathione reductase activity (EGR-AC) values suggesting better riboflavin status than the other groups. A similar trend was not seen with regard to pyridoxal phosphate. Milk riboflavin concentration was similar in all the groups except Group II where the levels were significantly higher. Milk pyridoxine concentration increased 3-4 fold after 1 month of lactation and continued to be at that level beyond 18 months. There was no correlation between the maternal riboflavin and milk riboflavin status or maternal pyridoxine and milk pyridoxine status. The higher milk riboflavin concentration among the Group II women was seen regardless of the women's riboflavin status in that group. OC-treated women did not show any significant deviations from women not using OCs.
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PMID:Relationship between maternal vitamins B2 and B6 status and the levels of these vitamins in milk at different stages of lactation. A study in a low-income group of Indian women. 395 16

The formation of pyridoxal and its phosphate from pyridoxamine phosphate by red cell haemolysates was measured in a centrifugal analyser by the formation of the fluorescent adduct with semicarbazide. Pyridoxal phosphate was found to react more rapidly than pyridoxal, thus permitting a distinction between the two products, and hence the measurement of phosphatase activity. Activity of the enzyme, pyridoxamine phosphate:oxygen oxidoreductase (deaminating) EC 1.4.3.5 (PPO) was measured in haemolysates from 72 Gambian women with evidence of riboflavin deficiency, and was repeated after 6 weeks of placebo or riboflavin supplementation. Those who received the riboflavin supplement responded with a marked increase in PPO activity, which was matched by a decrease in the activation coefficient (AC) of erythrocyte NAD(P)H2:glutathione oxidoreductase, EC 1.6.4.2 (glutathione reductase, EGR). No difference between the supplemented and unsupplemented groups was observed in the capacity of haemolysates to hydrolyse pyridoxal 5-phosphate, nor in the extent of activation of erythrocyte L-aspartate:2-oxoglutarate aminotransferase EC 2.6.1.1. by pyridoxal phosphate. Although the three subjects with low levels of D-glucose 6-phosphate: NADP 1-oxidoreductase EC 1.1.1.49 (G6P-D) had, as expected, correspondingly low AC's of EGR, their unsupplemented activities of PPO were in the same low range as those of the G6P-D-normal subjects, and they responded as G6P-D-normal subjects did to riboflavin supplementation. PPO thus does not appear to resemble EGR in retaining its flavin coenzyme during riboflavin depletion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A simple fluorimetric assay for pyridoxamine phosphate oxidase in erythrocyte haemolysates: effects of riboflavin supplementation and of glucose 6-phosphate dehydrogenase deficiency. 401 61

This study was conducted in order to assess the nutritional status of thiamin, riboflavin, pyridoxine, carotene, retinol, ascorbic acid, plasma iron, hemoglobin and plasma albumin of the elderly living in two cooperative farms (Kibbutzim), in Israel. Blood samples from elderly subjects aged 60 to 85 (33 women, 26 men), were collected for analysis. Thiamin, riboflavin and pyridoxine status were assessed by using enzymatic activation coefficient. Transketolase was used for determining thiamin status, glutathione reductase for determining riboflavin status and glutamate oxaloacetate transaminase for pyridoxine status. Transketolase activation coefficient ranged from 1.05-1.59 with a mean 1.18 and SEM 0.02, glutathione reductase coefficient ranged from 1.08-1.50 with a mean 1.25 and SEM 0.07 and glutamate oxaloacetate transaminase activation coefficient ranged from 1.71-2.15 with a mean 1.83 and SEM 0.06. Deficient levels were found in the following: Leucocyte ascorbic acid 5% of the population, hemoglobin 18%, plasma iron 20%, carotene 32% and plasma retinol 20%, thiamin 14% and riboflavin 32%. No deficient state was found in pyridoxine.
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PMID:Nutritional status in elderly population in kibbutzim. 407 7

The effect of haemolysis on the levels of commonly analysed plasma constituents was investigated in the common marmoset. Results were divided into a) low levels of extra haemolysis (less than 2 g/l plasma haemoglobin) and b) high levels of extra haemolysis (greater than 2 g/l plasma haemoglobin). Mean changes in plasma constituent levels were examined and the correlation with increased haemolysis measured. Large changes in malate dehydrogenase and lactate dehydrogenase were found at low levels of haemolysis. With higher levels of haemolysis there were statistically significant changes in the levels of alanine aminotransferase, isocitrate dehydrogenase, glutathione reductase, bilirubin, aspartate aminotransferase and sorbitol dehydrogenase. The significance of these findings is considered in relation to the interpretation of changes of plasma constituents as indicators of tissue/organ damage.
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PMID:The effect of haemolysis on some clinical chemistry parameters in the marmoset (Callithrix jacchus). 643 Nov 86

Differential enzymic analyses of the erythrocyte glutamic-oxaloacetic transaminase and the erythrocyte glutathione reductase of a patient with a 3-yr history of the carpal tunnel syndrome (CTS) revealed high deficiencies of both vitamin B-6 and riboflavin as based on approximately equal to 30% levels of the specific activities of these enzymes. Riboflavin for 5 months caused nearly complete disappearance of the CTS and caused no change in the specific activity of erythrocyte glutamic-oxaloacetic transaminase. Combined riboflavin and pyridoxine treatment increased (P less than 0.001) the specific activities of erythrocyte glutathione reductase and erythrocyte glutamic-oxaloacetic transaminase to normal levels with total disappearance of the CTS. Objectively, the strength of pinch of both hands increased (P less than 0.001) on treatment with riboflavin and further increased (P less than 0.001) on the combined treatment. For the first time, a significant riboflavin deficiency has been found to be related to CTS. Riboflavin therapy was effective biochemically, subjectively, and objectively, and riboflavin and pyridoxine were even more effective when concomitantly administered.
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PMID:Enzymology of the response of the carpal tunnel syndrome to riboflavin and to combined riboflavin and pyridoxine. 659 81

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.
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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.
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PMID:Thiamine, riboflavin and pyridoxine deficiency in psychiatric in-patients. 713 10

Unlike erythrocytes from elderly humans, red blood cells from old mice are not more sensitive than are cells from young animals to lysis in hypotonic solutions, probably because the mean corpuscular volume decreases rather than increases with age in this species. However, when subjected to an oxidant stress (sodium ascorbate) red blood cells from old animals accumulate more methemoglobin and fewer remain intact than is the case with red blood cells from young mice. The data suggest that this increased vulnerability to oxidative damage is manifest relatively early in the lifespan of red blood cells from old animals and is not solely a property of the older cells. The pathogenesis of the decreased resistance to peroxidation is not known, but it does not appear to be the result of changes in reduced glutathione, NADH: methemoglobin reductase, superoxide dismutase, glutathione reductase, glutamic-oxaloacetic transaminase, or glucose 6-phosphodehydrogenase.
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PMID:Age-related increase in erythrocyte oxidant sensitivity. 717 1


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