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Esterase

About: Esterase is a research topic. Over the lifetime, 7622 publications have been published within this topic receiving 168270 citations.


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Journal ArticleDOI
28 Feb 1969-Science
TL;DR: In the freshwater fish Catostomus clarkii, the frequency of alleles for polymorphic serum esterase varies with latitude, and coefficients of selection used to calculate allelic equilibrium within populations are derived from the activity profiles of the genotypes.
Abstract: In the freshwater fish Catostomus clarkii, the frequency of alleles for polymorphic serum esterase varies with latitude. The activity of the allele more frequent in southern populations increases as temperature increases from 0 ° to 37 °C, whereas activity of the allele more frequent in northern populations increases as temperature decreases. Coefficients of selection used to calculate allelic equilibrium within populations are derived from the activity profiles of the genotypes.

213 citations

Journal ArticleDOI
TL;DR: Streptomyces olivochromogenes FAE showed activity against methyl ferulate, methyl sinapinate and methyl p-coumarate, but at a level 420-fold less than the A. niger esterase, which shows the necessity for C-3 on the phenol ring to be methoxylated and the aliphatic region of the substrate to be unsaturated.
Abstract: An inducible ferulic acid esterase (FAE-III) has been isolated, purified and partially characterized from Aspergillus niger after growth on oat spelt xylan. The purification procedure utilized ammonium sulphate precipitation, hydrophobic interaction and anion-exchange chromatography. The purified enzyme appeared almost pure by SDS-PAGE, with an apparent M r of 36000. A single band, corresponding to a pl of 3·3 was observed on isoelectric focusing. With methyl ferulate as substrate, the enzyme had a specific activity of 67 IU (mg protein)-1, pH and temperature optima of 5 and 55–60 °C, respectively, and a Km of 2·08 mM and a V max of 175 μmol min-1 (mg protein)-1. The enzyme was also active upon methyl sinapinate, methyl-3,4-dimethoxy cinnamate and methyl p-coumarate, but not benzoic acid methyl esters or methyl caffeate. Similarly, Streptomyces olivochromogenes FAE showed activity against methyl ferulate, methyl sinapinate and methyl p-coumarate, but at a level 420-fold less (on methyl ferulate) than the A. niger esterase. No activity was detected against the benzoate methyl esters. For both enzymes, this shows the necessity for C-3 on the phenol ring to be methoxylated and the aliphatic region of the substrate to be unsaturated. The specific activity of FAE-III on destarched wheat bran was 31 U (mg protein)-1 in the presence of Trichoderma viride xylanase and 3 U (mg protein)-1 in the absence. Apparent pH dependent binding of A. niger FAE-III to microcrystalline cellulose was also demonstrated.

210 citations

Journal ArticleDOI
TL;DR: It is shown that the formation of C'1 esterase during complement fixation is mediated by proteolytic processes, and the possible inhibition of C’1q by soybean trypsin inhibitor is in agreement with this hypothesis.
Abstract: The formation of C'1 esterase from C'1, the first component of complement, may be brought about by the action of plasmin or trypsin upon C'1s, a subcomponent of C'1. These enzymes also decrease the esterolytic activity of C'1 esterase. The formation of C'1 esterase was demonstrated by measuring the appearance of an agent or agents with esterolytic properties and the capacity to inactivate C'2 and C'4, attributes of C'1 esterase. The activity of the agent which evolved was blocked by serum inhibitor of C'1 esterase. The implications of these observations, that the formation of C'1 esterase during complement fixation is mediated by proteolytic processes, are under study. The possible inhibition of C'1q by soybean trypsin inhibitor is in agreement with this hypothesis.

207 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202391
2022209
202183
2020112
2019107
2018129