Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The hydroxyl groups of poly(ethyleneglycol) have been esterified (partly) with a number of carboxylic acids. When these esters are included in dextranpoly(ethyleneglycol)-water biphasic systems the partitions of proteins and membranes between the two phases (and the interface) are in some cases strongly affected. The affinity of serum albumin for the poly(ethyleneglycol)-rich phase is strongly increased when the fatty acid group consists of more than 10 carbon atoms. The partition also depends on the number of double bonds in the fatty acid. A corresponding relationship is found for membranes from spinach chloroplasts. The partitions of ovalbumin, lysozyme (EC 3.2.1.17) and ribonuclease (EC 3.1.4.22) are not influenced by the fatty acid esters. Esters of dibasic carboxylic acids show a minute but marked effect on the partition of proteins in general while malate and tartrate esters affect strongly the partition of chloroplast membranes. The partitions of both proteins and membranes are influenced by poly(ethyleneglycol) deoxycholate. Experiments with malate dehydrogenase (EC 1.1.1.37), lactate dehydrogenase (EC 1.1.1.27), fumarase (EC 4.2.1.2), enolase (EC 4.2.1.11) and glutamate-ocaloacetate transaminase (EC 2.6.1.1) show that their partitions, measured on enzymic activity basis, is changed when esters of benzoic, linolenic, tartaric or deoxycholic acid are included in the biphasic system. The mechanism behind the effect of the esterified poly (ethyleneglycol) on the partition of biomaterial, in this type of aqueous biphasic systems, is discussed in terms of a direct binding of the esters to the partitioned material.
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PMID:The effect of poly(ethyleneglycol) esters on the partition of proteins and fragmented membranes in aqueous biphasic systems. 99 68

Fumarase (EC 4.2.1.2) and mitochondrial L-malate dehydrogenase (EC 1.1.1.37) were both inhibited by NaAuCl4 and KAuBr4. The inhibition for both was measured as a function of gold complex concentration and aquation time, and the NaAuCl4 inhibition was also measured in the presence of 0.15 M NaCl. Regeneration of the enzyme activity after NaAuCl4 inhibition using L-cysteine, L-methionine and NaCN was also investigated. Sodium dodecyl sulfate (SDS) acrylamide gel electrophoresis and amino acid analysis was performed on the NaAuCl4 inhibited enzymes as well as on ribonuclease A (EC 3.1.26.2), lysozyme (EC 3.2.1.17) and liver alcohol dehydrogenase (EC 1.1.1.1). It was observed that the inhibition was proportional to the gold complex concentration but decreased markedly after aquation of the complex. In the presence of NaCl the initial rate of inactivation is essentially unaffected unless the complex has been aquated and then the initial rate is increased. Gel electrophoresis on gold complex-enzyme mixtures show polymerization for ribonuclease and lysozyme and amino acid analysis indicates that no oxidation has taken place. From these results, a binding mechanism is postulated for the inhibition of the dehydrogenases by direct displacement of a halide ligand, probably by two groups on the enzyme, at least one of which may be a sulfur containing acid.
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PMID:Inhibition of two mitochondrial enzymes by gold (III) halo complexes. Evidence for a binding mechanism. 715 Dec 34