Document Detail


Fractionation and kinetic properties of rat liver and kidney methionine adenosyltransferase isozymes.
MedLine Citation:
PMID:  6849873     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Three isozymes of methionine adenosyltransferase (EC 2.5.1.6; MAT-I, -II, and -III) exist in normal rat liver and are conveniently purified (MAT-III to homogeneity) by a three-step column chromatography procedure. MAT-I shows Michaelis-Menten kinetics with a Km (L-methionine) of 41 microM and a molecular weight of 208 000 and is slightly inhibited by S-adenosyl-L-methionine (Adomet). MAT-II, which is also the only isozyme found in normal rat kidney, shows negative cooperativity with a Hill coefficient of 0.7. It has a L-methionine concentration required for half-maximal velocity [S0.5(Met)] of 8 microM and a molecular weight of 120 000 and is strongly inhibited by Adomet. MAT-I and -II comprise 15% and 5%, respectively, of total MAT activity in rat liver. The predominant isozyme in rat liver, MAT-III, demonstrates positive cooperativity with a Hill coefficient of 1.8. It has a molecular weight of 97 000 and apparently consists of two subunits of identical molecular weight (47 000). This liver-specific isozyme is strongly activated by both dimethyl sulfoxide and Adomet and has a S0.5(Met) of 215 microM.
Authors:
D M Sullivan; J L Hoffman
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Biochemistry     Volume:  22     ISSN:  0006-2960     ISO Abbreviation:  Biochemistry     Publication Date:  1983 Mar 
Date Detail:
Created Date:  1983-07-08     Completed Date:  1983-07-08     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370623     Medline TA:  Biochemistry     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1636-41     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Chromatography, Ion Exchange
Female
Isoenzymes / isolation & purification*,  metabolism
Kidney / enzymology*
Kinetics
Liver / enzymology*
Methionine Adenosyltransferase / isolation & purification*,  metabolism
Molecular Weight
Rats
Rats, Inbred Strains
Transferases / isolation & purification*
Grant Support
ID/Acronym/Agency:
CA 22166/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/Isoenzymes; EC 2.-/Transferases; EC 2.5.1.6/Methionine Adenosyltransferase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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