CHEMICAL MODIFICATION OF ARGINYL RESIDUES IN RABBIT MUSCLE PYRUVATE-KINASE

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dc.contributor.authorCARDEMIL, E
dc.contributor.authorEYZAGUIRRE, J
dc.date.accessioned2025-01-23T19:44:18Z
dc.date.available2025-01-23T19:44:18Z
dc.date.issued1981
dc.description.abstractRabbit muscle pyruvate kinase was inactivated with the arginine-specific reagent 2,3-butanedione, in borate buffer, following psuedo-first-order kinetics. Graphical representation of the kobs as a function of inactivator concentration follows a straight line which is compatible with the following mechanism: .**GRAPHIC**. Values for k1 = 4.6 M-1 min-1 and k1 = 0.0022 min-1 can be estimated. The order of the reaction was near 1, suggesting that the modification of a single amino acid residue of the enzyme is responsible for its inactivation. Almost full catalytic activity was recovered when excess butanedione and borate buffer were removed by Sephadex G-25 gel filtration, which suggests that only arginyl residues were modified. The inactivation was partially prevented by phosphoenolypyruvate in the presence of K+ and Mg2+, but not by the competitive inhibitors lactate and bicarbonate, or ADP, with or without added metal ions. Mg2+ alone increased the rate of inactivation. Quantification of residual arginine residues after chemical modification, using amino acid analysis, gives no precise correlation between the number of residues modified and the residual activity; however, .apprx. 4 residues react per enzyme subunit, showing the presence of reactive, nonessential arginines. One essential arginyl residue is present per subunit in rabbit muscle pyruvate kinase, and this residue is probably located near the binding site of the phosphate group of phosphoenolpyruvate.
dc.fuente.origenWOS
dc.identifier.issn0004-0533
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/100004
dc.identifier.wosidWOS:A1981MZ04600004
dc.issue.numero2
dc.language.isoen
dc.pagina.final128
dc.pagina.inicio123
dc.revistaArchivos de biologia y medicina experimentales
dc.rightsacceso restringido
dc.subject.ods03 Good Health and Well-being
dc.subject.odspa03 Salud y bienestar
dc.titleCHEMICAL MODIFICATION OF ARGINYL RESIDUES IN RABBIT MUSCLE PYRUVATE-KINASE
dc.typeartículo
dc.volumen14
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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