Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
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Enzyme
Compound
Query: EC:3.5.1.1 (
asparaginase
)
2,695
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
In studies on kinetics of thermoinactivation of glutaminase (
asparaginase
) from Ps. arantiaca BKMB-548 at 50 degrees and pH 7.0 in presence or in absence of L-glutamate the enzyme inactivation was found to obey the first order equation. Both the glutaminase and
asparaginase
activities decreased at a similar rate. L-Glutamate stabilized the enzyme due to direct interaction with its molecule. Stability of the complex formed was evaluated quantitatively. L-Glutamate reacted apparently with a specific site on the surface of the enzyme molecule; Kdiss was 0.42 +/- 0.03 mM at pH 7.0 and 50 degrees. No cooperative effect was found. L-Aspartate protected the enzyme completely; stabilizing effects of L-cysteine, L-serine and glycine were similar to the effect of L-glutamate (94%, 84%, 83% and 82%, respectively). At the same time, glutarate, succinate, alpha-ketobutyrate, alpha-ketoglutarate,
gamma-aminobutyrate
and N-benzoyl glutamate did not exhibit the stabilization effect. The data obtained suggest that the high stabilizing effect might exhibit only the substances containing simultaneously free alpha-NH2 and alpha-COOH groups in a molecule, whereas presence of COOH groups at beta--or gamma-carbon atoms was not essential for the stabilizing effect.
...
PMID:[Thermostabilization of glutamin(asparagin)ase from Pseudomonas aurantica BKMB-548]. 402 28
A man with a chronic schizophrenia-like psychotic disorder had fasting plasma asparagine concentrations that were consistently 4 to 8 SD above the normal level. Asparagine levels were also high in his cerebrospinal fluid (CSF) and erythrocytes. Ornithine, proline, and glutamate concentrations were irregularly high in fasting plasma, and
gamma-aminobutyric acid
(
GABA
) concentrations were elevated in CSF. Whether or not these biochemical abnormalities were related to the psychotic disorder is unclear. However, increased asparagine concentrations, possibly due to an enzymatic deficiency of
asparaginase
, could lead to deregulation of polyamine biosynthesis and to excessive production of
GABA
from putrescine. These biochemical changes could in turn cause disordered brain function. A search in mentally ill patients for metabolic abnormalities involving asparagine, or other amino acids, might hasten elucidation of the biochemical basis of the schizophrenias.
...
PMID:Hyperasparaginemia in a schizophrenic patient. 683 Sep 27
Net balances of amino acids were constructed for stages of development of a leaf of white lupin (Lupinus albus L.) using data on the N economy of the leaf, its exchanges of amino acids through xylem and phloem, and net changes in its soluble and protein-bound amino acids. Asparagine, aspartate, and
gamma-aminobutyrate
were delivered to the leaf in excess of amounts consumed in growth and/or phloem export. Glutamine was supplied in excess until full leaf expansion (20 days) but was later synthesized in large amounts in association with mobilization of N from the leaf. Net requirements for glutamate, threonine, serine, proline, glycine, alanine, valine, isoleucine, leucine, tyrosine, phenylalanine, histidine, lysine, and arginine were met mainly or entirely by synthesis within the leaf. Amides furnished the bulk of the N for amino acid synthesis, asparagine providing from 24 to 68%. In vitro activity of
asparaginase
(
EC 3.5.1.1
) exceeded that of asparagine:pyruvate aminotransferase (EC 2.6.1.14) during early leaf expansion, when in vivo estimates of asparagine metabolism were highest. Thereafter, aminotransferase activity greatly exceeded that of
asparaginase
. Rates of activity of one or both asparagine-utilizing enzymes exceeded estimated rates of asparagine catabolism throughout leaf development. In vitro activities of glutamine synthetase (EC 6.3.1.2) and glutamate synthase (EC 1.4.7.1) were consistently much higher than that of glutamate dehydrogenase (EC 1.4.1.3), and activities of the former two enzymes more than accounted for estimated rates of ammonia release in photorespiration and deamidation of asparagine.
...
PMID:Amino Acid transport and metabolism in relation to the nitrogen economy of a legume leaf. 1666 17
