KFU. Card publication. Steady-state kinetic analysis of human cholinesterases over wide concentration ranges of competing substrates.

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FEDERAL UNIVERSITY

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STEADY-STATE KINETIC ANALYSIS OF HUMAN CHOLINESTERASES OVER WIDE CONCENTRATION RANGES OF COMPETING SUBSTRATES.

Form of presentation

Articles in international journals and collections

Year of publication

2022

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Authors, employees of KFU

Mukhametgalieva Aliya Rafikovna, author

Bibliographic description in the original language

Mukhametgalieva A.R., Lushchekina S.V., Aglyamova A.R., Masson P. Steady-state kinetic analysis of human cholinesterases over wide concentration ranges of competing substrates. // Biochim Biophys Acta Proteins Proteom. - 2022. - V. - 1870, �1. - 140733. doi: 10.1016/j.bbapap.2021.140733.

Annotation

ubstrate competition for human acetylcholinesterase (AChE) and human butyrylcholinesterase (BChE) was studies under steady-state conditions using wide range of substrate concentrations. Competing couples of substates were acetyl-(thio)esters. Phenyl acetate (PhA) was the reporter substrate and competitor were either acetylcholine (ACh) or acetylthiocholine (ATC). The common point between investigated substrates is that the acyl moiety is acetate, i.e. same deacylation rate constant for reporter and competitor substrate. Steady-state kinetics of cholinesterase-catalyzed hydrolysis of PhA in the presence of ACh or ATC revealed 3 phases of inhibition as concentration of competitor increased: a) competitive inhibition, b) partially mixed inhibition, c) partially uncompetitive inhibition for AChE and partially uncompetitive activation for BChE. This sequence reflects binding of competitor in the active centrer at low concentration and on the peripheral anionic site (PAS) at high concentration. In particular, it showed that binding of a competing ligand on PAS may affect the catalytic behavior of AChE and BChE in an opposite way, i.e. inhibition of AChE and activation of BChE, regardless the nature of the reporter substrate. For both enzymes, progress curves for hydrolysis of PhA at very low concentration (≪Km) in the presence of increasing concentration of ATC showed that: a) the competing substrate and the reporter substrate are hydrolyzed at the same time, b) complete hydrolysis of PhA cannot be reached above 1 mM competing substrate. This likely results from accumulation of hydrolysis products (P) of competing substrate and/or accumulation of acetylated enzyme?P complex that inhibit hydrolysis of the reporter substrate.

Keywords

Acetylcholinesterase; Butyrylcholinesterase; Catalytic parameters; Competing substrates; Partial inhibition; Progress curve.

The name of the journal

Biochimica et Biophysica Acta - Proteins and Proteomics

URL

https://linkinghub.elsevier.com/retrieve/pii/S1570-9639(21)00139-4

Please use this ID to quote from or refer to the card

https://repository.kpfu.ru/eng/?p_id=280337&p_lang=2

Full metadata record

Field DC	Value	Language
dc.contributor.author	Mukhametgalieva Aliya Rafikovna	ru_RU
dc.date.accessioned	2022-01-01T00:00:00Z	ru_RU
dc.date.available	2022-01-01T00:00:00Z	ru_RU
dc.date.issued	2022	ru_RU
dc.identifier.citation	Mukhametgalieva A.R., Lushchekina S.V., Aglyamova A.R., Masson P. Steady-state kinetic analysis of human cholinesterases over wide concentration ranges of competing substrates. // Biochim Biophys Acta Proteins Proteom. - 2022. - V. - 1870, �1. - 140733. doi: 10.1016/j.bbapap.2021.140733.	ru_RU
dc.identifier.uri	https://repository.kpfu.ru/eng/?p_id=280337&p_lang=2	ru_RU
dc.description.abstract	Biochimica et Biophysica Acta - Proteins and Proteomics	ru_RU
dc.description.abstract	ubstrate competition for human acetylcholinesterase (AChE) and human butyrylcholinesterase (BChE) was studies under steady-state conditions using wide range of substrate concentrations. Competing couples of substates were acetyl-(thio)esters. Phenyl acetate (PhA) was the reporter substrate and competitor were either acetylcholine (ACh) or acetylthiocholine (ATC). The common point between investigated substrates is that the acyl moiety is acetate, i.e. same deacylation rate constant for reporter and competitor substrate. Steady-state kinetics of cholinesterase-catalyzed hydrolysis of PhA in the presence of ACh or ATC revealed 3 phases of inhibition as concentration of competitor increased: a) competitive inhibition, b) partially mixed inhibition, c) partially uncompetitive inhibition for AChE and partially uncompetitive activation for BChE. This sequence reflects binding of competitor in the active centrer at low concentration and on the peripheral anionic site (PAS) at high concentration. In particular, it showed that binding of a competing ligand on PAS may affect the catalytic behavior of AChE and BChE in an opposite way, i.e. inhibition of AChE and activation of BChE, regardless the nature of the reporter substrate. For both enzymes, progress curves for hydrolysis of PhA at very low concentration (≪Km) in the presence of increasing concentration of ATC showed that: a) the competing substrate and the reporter substrate are hydrolyzed at the same time, b) complete hydrolysis of PhA cannot be reached above 1 mM competing substrate. This likely results from accumulation of hydrolysis products (P) of competing substrate and/or accumulation of acetylated enzyme?P complex that inhibit hydrolysis of the reporter substrate.	ru_RU
dc.language.iso	ru	ru_RU
dc.subject		ru_RU
dc.title	Steady-state kinetic analysis of human cholinesterases over wide concentration ranges of competing substrates.	ru_RU
dc.type	Articles in international journals and collections	ru_RU