scispace - formally typeset
Search or ask a question
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.


Papers
More filters
Journal ArticleDOI
TL;DR: This review examines the complex dynamic behavior of the protein that enables regulated fast and specific catalysis to occur and describes how three conformations of the enzyme provide a foundation for the catalytic cycle.

139 citations

Journal ArticleDOI
TL;DR: The preference of cobra venom phospholipase A2 for PC over PE in Triton X-100 mixed micelles appears to be an effect on k3 (catalytic rate) rather than a effect on the apparent binding of phospholIPid in either step of the reaction.

139 citations

Journal ArticleDOI
TL;DR: Kinetic analysis revealed that the deacylation of the enzyme is the rate-limiting step in substrate hydrolysis, and this enzyme was found to also split other ester derivatives of SN-38 besides CPT-11.
Abstract: A rat serum enzyme that catalyzes the conversion of a pro-drug, 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin (CPT-11), to an anticancer drug, 7-ethyl-10-hydroxycamptothecin (SN-38), was purified and its properties were characterized. The enzyme was purified by column chromatography on diethylaminoethyl Toyopearl 650M, QAE-Sephadex, Sephadex G-150, Con A-Sepharose and high performance liquid chromatography with an ion-exchanger column. It was most active at pH 7.5 and was stable at pH 4-9 for 1 h at 30 degrees C. The molecular weight was estimated to be 60 and 57 kDa by gel filtration and sodium dodecylsulfate-polyacrylamide gel electrophoresis methods, respectively, and the isoelectric point was 4.6, as determined by isoelectric focusing. The Km value for CPT-11 was 0.28 microM. This enzyme was inhibited by diisopropyl phosphorofluoridate (DFP) and phenylmethanesulfonyl fluoride (PMSF) but insensitive to eserine, p-chloromercuribenzoate (PCMB) and ethylenediaminetetraacetate (EDTA). The enzyme also hydrolyzed p-nitrophenylacetate (p-NPA), a commonly used substrate for esterases, but was not active toward acetylcholine, suggesting that the enzyme is a carboxylesterase[EC 3.1.1.1]. During the hydrolyses of CPT-11 and p-NPA, an initial burst phenomenon similar to that found in the alpha-chymotrypsin-catalyzed hydrolysis of p-NPA was observed. Kinetic analysis revealed that the deacylation of the enzyme is the rate-limiting step in substrate hydrolysis. This enzyme was found to also split other ester derivatives of SN-38 besides CPT-11.

139 citations

Journal ArticleDOI
TL;DR: Based on the observed activity, it appears that the sulfhydryl oxidase could be involved in the biosynthesis of disulfide bonds in certain proteins.

139 citations

Journal ArticleDOI
TL;DR: It would appear that the complex which P-450LM2 forms with its substrate allows considerable movement of the substrate molecule, such that most of the hydrogens in the substrate are exposed to the enzymatic hydrogen abstractor.

139 citations


Network Information
Related Topics (5)
Oxide
213.4K papers, 3.6M citations
86% related
Carbon nanotube
109K papers, 3.6M citations
83% related
Raman spectroscopy
122.6K papers, 2.8M citations
83% related
Thin film
275.5K papers, 4.5M citations
82% related
Silicon
196K papers, 3M citations
82% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202214
2021807
20201,053
20191,064
20181,112
20171,024