Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.4.17 (adenosine deaminase)
 5,206 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In isolated hepatocytes from fasted rats, 0.5 mM adenosine inhibited gluconeogenesis from glutamine, lactate and pyruvate. This inhibition was due to adenosine conversion through adenosine kinase. An increase in ketone body release was only observed in the presence of lactate or pyruvate, and the two phenomena (i.e. inhibition of gluconeogenesis and increased ketone-body release) were linked. With alanine, dihydroxyacetone or serine as substrates, adenosine did not change gluconeogenesis; however, its conversion through adenosine kinase also inhibited gluconeogenesis. With asparagine as substrate, 0.5 mM adenosine increased gluconeogenesis; this increase was due to adenosine conversion through adenosine deaminase. However, adenosine conversion through adenosine kinase inhibited gluconeogenesis from asparagine. Thus, whatever the substrate used, adenosine conversion through adenosine kinase inhibited gluconeogenesis. The inhibitory effect of adenosine on gluconeogenesis cannot be related to the decrease in Pi concentration and to the increase in ATP pool. Beside its effect on gluconeogenesis, adenosine inhibited ketogenesis measured without added substrate; adenosine conversion through adenosine kinase was also involved in the inhibition of ketogenesis.
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PMID:Metabolism of adenosine through adenosine kinase inhibits gluconeogenesis in isolated rat hepatocytes. 215 47

The activities of alanine-, aspartate- and branched-chain amino-acid transaminases, glutamine synthetase, glutamate dehydrogenase and adenylate deaminase in white adipose tissue of adult male rats have been determined in animals submitted to 12-h cold exposure (4 degrees C) or to 24-h food deprivation. Starvation resulted in small changes in glutamate dehydrogenase and alanine transaminase when expressed per unit of protein weight, inducing an increase in branched-chain amino-acid transaminase and glutamine synthetase. Cold exposure showed the same effects as starvation with respect to glutamate dehydrogenase and alanine transaminase, but induced increases in glutamine synthetase and aspartate transaminase. It is concluded that starvation increases the handling of some amino acids by white adipose tissue and the detoxification of the ammonia thus evolved. The changes observed suggest a different pattern of amino-acid metabolism enzyme changes with either cold or starvation.
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PMID:Amino-acid metabolism enzyme activities in rat white adipose tissue. 243 May 32

To contribute to our understanding of nitrogen metabolism in the developing chick we have studied in liver, intestine and yolk sac membrane the ontogeny of both aspartate- and alanine transaminases, glutamate dehydrogenase, adenylate deaminase, glutamine synthetase and xanthine dehydrogenase activities. Liver enzyme activities were much higher than those of the same enzymes in intestine and yolk sac membrane, the latter having the lowest activities. In the liver, both alanine transaminase and glutamate dehydrogenase increased their activity just before hatching, xanthine dehydrogenase and glutamine synthetase develop their highest activity just after hatching, while aspartate transaminase and adenylate deaminase attained the highest levels just with adulthood. From the pattern of enzyme activity in yolk sac membrane and intestine it can be inferred that after hatching, the amino-acid metabolism in these tissues is considerably enhanced, with higher production of ammonia from amino acids, as indicated by the rise in adenylate deaminase, as well as increased potentiality in production of both alanine and glutamine. It can be concluded that hatching coincides with a deep change of pace in amino-acid metabolism in the organs studied fully comparable with that observed in Mammals at the end of lactation, with the difference that the adaptation to the new diet in the case of the chick is much more sudden than weaning is for the rat.
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PMID:Amino-acid metabolism enzyme activities in the liver, intestine and yolk sac membrane of developing domestic fowl. 243 52

In 15%-20% of children with severe combined immunodeficiency (SCID), the underlying defect is adenosine deaminase (ADA) deficiency. The overall goal of our research has been to identify the precise molecular defects in patients with ADA-deficient SCID. In this study, we focused on a patient whom we found to have normal sized ADA mRNA by Northern analysis and an intact ADA structural gene by Southern analysis. By cloning and sequencing this patient's ADA cDNA, we found a C-to-T point mutation in exon 11. This resulted in the amino acid substitution of a valine for an alanine at position 329 of the ADA protein. Sequence analysis revealed that this mutation created a new BalI restriction site. Using Southern analyses, we were able to directly screen individuals to determine the frequency of this mutation. By combining data on eight families followed at our institution with data on five other families reported in the literature, we established that five of 13 patients (seven of 22 alleles) with known or suspected point mutations have this defect. This mutation was found to be associated with three different ADA haplotypes. This argues against a founder effect and suggests that the mutation is very old. In summary, a conservative amino acid substitution is found in a high proportion of patients with ADA deficiency; this can easily be detected by Southern analysis.
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PMID:A high proportion of ADA point mutations associated with a specific alanine-to-valine substitution. 277 32

Incubation of hepatocytes from 24 h-starved rats in the presence of 0.5 mM-adenosine decreased gluconeogenesis from lactate, but not from alanine. The inhibition of gluconeogenesis was associated with a stimulation of ketone-body production and an inhibition of pyruvate oxidation. These metabolic changes were suppressed in the presence of iodotubercidin (an inhibitor of adenosine kinase), but were reinforced in the presence of deoxycoformycin (an inhibitor of adenosine deaminase); 2-chloroadenosine induced no change in gluconeogenesis from lactate. These data indicate that the inhibition of gluconeogenesis by adenosine probably results from its conversion into adenine nucleotides. In the presence of lactate or pyruvate, but not with alanine or asparagine, this conversion resulted in a decrease in the [ATP]/[ADP] ratio in both mitochondrial and cytosolic compartments. Adenosine decreased the Pi concentration with all gluconeogenic substrates.
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PMID:The mechanism by which adenosine decreases gluconeogenesis from lactate in isolated rat hepatocytes. 282 38

Activities of alanine and aspartate transaminases, glutamine synthetase, adenylate deaminase, glutamate and xanthine dehydrogenases and lactate dehydrogenase were measured in leg and breast muscles of developing chicks from day 10 in ovo to day 5 of free life, and compared with measurements for adult hens. Xanthine dehydrogenase activity was low in both muscles with adult levels attained on day 15 in ovo. Glutamine synthetase for chicks was maintained higher during development than for adults in both muscles. Minor differences were observed between both muscles in all enzymes tested up to day 18. With low embryonic values and important rises before hatching, the differences were initiated in the posthatching period. Important differences were observed between adult levels of activity. Leg muscle revealed higher enzyme values except for lactate dehydrogenase and indistinguishable levels for adenylate deaminase and xanthine dehydrogenase in both muscles. Alanine, instead of glutamine, is postulated as the main nitrogen transport between muscle and liver in the domestic fowl.
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PMID:Patterns of amino acid enzyme in domestic fowl breast and leg muscle during development. 286 43

There was a nil arginase and serine dehydratase activities in interscapular brown adipose tissue, but the activity of adenylate deaminase, glutamine synthetase, glutamate dehydrogenase and the aspartate, alanine and branched chain amino acid transaminases was higher than those of white adipose tissue; the differences were diminished when expressed per unit of protein weight. Brown adipose tissue enzyme activities were in a range between those of liver and muscle. The high amino acid handling capabilities, together with its physiological role, suggest that brown adipose tissue can metabolize significant amounts of amino acids, its enzyme pattern being different both from white adipose tissue, as well as of liver and muscle.
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PMID:Activities of enzymes of amino acid metabolism in rat brown adipose tissue. 287 38

The activities of alanine and aspartate transaminases, adenylate deaminase, glutamine synthetase and glutamate and xanthine dehydrogenases have been measured in liver, yolk sac membrane, intestine and breast and leg muscle of domestic fowl hatchlings receiving for 3 or 5 days either a standard diet or hard boiled eggwhite as well as in 3 or 5 days starved animals. The patterns of activation of amino acid metabolism enzymes were fully comparable in protein-fed and starved groups with respect to fed controls; the differences with respect to the latter became more marked in 5- than in 3-days old chicks. In 5-days old chicks intestine alanine transaminase activity increased in parallel to that of liver in protein-fed animals but not in those starved, in agreement with an enhanced alanine transfer between both organs under this situation. Both, starvation and protein-feeding, induced a general decrease in the amino acid metabolizing ability of muscle. Glutamine (but not alanine) synthetizing capabilities were enhanced.
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PMID:Effect of starvation and a protein diet on the amino acid metabolism enzyme activities of the organs of domestic fowl hatchlings. 287 42

The effect of 24-hr starvation on the amino acid pool composition and its concentration ratios with respect to blood and plasma as well as the activities of alanine, aspartate and branched chain amino acid transaminases, glutamate dehydrogenase, glutamine synthetase and adenylate deaminase have been studied in rat brown adipose tissue. Starvation induced a considerable decrease of pool amino acid concentration. Alanine and taurine were the amino acids in which the decrease was more marked. Small changes were observed in the activities of the enzymes studied, with decreases only in glutamate dehydrogenase and adenylate deaminase. These changes agree with a decrease in amino acid utilization in this tissue induced by starvation.
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PMID:Effect of 24-hour starvation on amino acid pool composition and enzyme activities of rat brown adipose tissue. 288 93

The amino acid pool composition and its concentration ratios with respect to blood and plasma, as well as the activities of alanine, aspartate and branched chain amino acid transaminases, glutamine synthetase, adenylate deaminase and glutamate dehydrogenase have been studied in the interscapular brown adipose tissue of control, 12-h cold-exposed and 15-day cold-acclimated rats. Cold temperature affected the amino acid metabolism and pool composition more intensely after 15 days than after 12-h cold-exposure, even though the patterns of change were very similar in both groups. Cold temperatures induced a decrease in glutamine and an increase in glutamate concentration in the tissue. This probably increased the metabolism of branched chain amino acids and caused a decrease in adenylate deaminase activity. It also seemed to increase alanine utilization. We concluded that amino acid metabolism in brown adipose tissue is enhanced by cold temperature acclimation.
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PMID:Effect of cold-temperature exposure and acclimation on amino acid pool changes and enzyme activities of rat brown adipose tissue. 288 9


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