Topic
Substrate (chemistry)
About: Substrate (chemistry) is a research topic. Over the lifetime, 35902 publications have been published within this topic receiving 740722 citations. The topic is also known as: enzyme substrate.
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TL;DR: This simple, accurate, and reproducible colorimetric method for determining the activity of angiotensin-I converting enzyme is based upon colorimetry of the quinoneimine dye produced from the substrate p-hydroxyhippuryl-L-histidyl- L-leucine by action of this enzyme through the following series of reactions.
Abstract: This simple, accurate, and reproducible colorimetric method for determining the activity of angiotensin-I converting enzyme is based upon colorimetry of the quinoneimine dye produced from the substrate p-hydroxyhippuryl-L-histidyl-L-leucine by action of this enzyme through the following series of reactions. The enzyme acts on the substrate to yield p-hydroxyhippuric acid and L-histidyl-L-leucine. The former is then hydrolyzed in the presence of hippuricase to produce p-hydroxybenzoic acid and glycine. Finally, oxidative coupling of p-hydroxybenzoic acid with 4-aminoantipyrine is catalyzed by peroxidase in the presence of hydrogen peroxide, producing a quinoneimine dye, the concentration of which is measured at its absorbance maximum at 505 nm to evaluate the activity of ACE. The Km value for the above-mentioned substrate is 0.32 mmol/L, the optimum pH is 8.3. Results by the present method and Cushman and Cheung's method (Biochem. Pharmacol. 20: 1637, 1971) correlate closely (r = 0.986). The within-run CV is 2.93%.
255 citations
TL;DR: Analysis of the protein-ligand interactions helps to delineate the structural determinants of substrate specificity and provides guidance for reengineering the enzyme to further improve its utility for biotechnological applications.
254 citations
TL;DR: PcGH61D, the gene product of an open reading frame in the genome of Phanerochaete chrysosporium, is an enzyme that cleaves cellulose using a metal-dependent oxidative mechanism that leads to generation of aldonic acids.
Abstract: Many fungi growing on plant biomass produce proteins currently classified as glycoside hydrolase family 61 (GH61), some of which are known to act synergistically with cellulases. In this study we show that PcGH61D, the gene product of an open reading frame in the genome of Phanerochaete chrysosporium, is an enzyme that cleaves cellulose using a metal-dependent oxidative mechanism that leads to generation of aldonic acids. The activity of this enzyme and its beneficial effect on the efficiency of classical cellulases are stimulated by the presence of electron donors. Experiments with reduced cellulose confirmed the oxidative nature of the reaction catalyzed by PcGH61D and indicated that the enzyme may be capable of penetrating into the substrate. Considering the abundance of GH61-encoding genes in fungi and genes encoding their functional bacterial homologues currently classified as carbohydrate binding modules family 33 (CBM33), this enzyme activity is likely to turn out as a major determinant of microbial biomass-degrading efficiency.
253 citations
TL;DR: The crystal structure reveals that during evolution, only the overall features of the enzyme have been conserved with respect to Escherichia coli, and the location of the active site at the bottom of a large valley flanked by an interfacial crown-shaped domain and a domain containing an extra metal ion on the other side suggest that the substrate of PLAP could be a specific phosphorylated protein.
253 citations
TL;DR: Results demonstrated viable approach for utilization of this huge biomass by solid-state fermentation for the production of industrial enzymes due to low cost and abundant availability of cake during biodiesel production.
252 citations