AFFINITY LABELING OF RABBIT MUSCLE PYRUVATE-KINASE WITH DIALDEHYDE-ADP

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dc.contributor.authorHINRICHS, MV
dc.contributor.authorEYZAGUIRRE, J
dc.date.accessioned2025-01-23T19:44:03Z
dc.date.available2025-01-23T19:44:03Z
dc.date.issued1982
dc.description.abstractPeriodate-oxidized ADP (dialdehyde-ADP) inactivates rabbit muscle pyruvate kinase and combines irreversibly to the enzyme. This inactivation is first-order with respect to dialdehyde-ADP and follows saturation kinetics, indicating that the enzyme first forms a reversible complex with the inactivator. Low Mg2+ concentrations stimulate the rate of inactivation, while higher concentrations have a protective effect. ADP and ATP, especially in the presence of Mg2+, protect very strongly against inactivation, while phosphoenolpyruvate and pyruvate are less effective. Dialdehyde-ADP is not a substrate, but acts as competitive inhibitor of ADP, with a KI of 4.5 mM. The analog has somewhat lower affinity to the enzyme than Mg-ADP, which has a Kd of 1.2 mM. Based on kinetic data, 1 molecule of reagent must combine per enzyme active site in order to inactivate the enzyme. Incorporation of [14C]dialdehyde-ADP into the enzyme and treatment of the data by the Tsou plot shows that 6-7 residues/subunit react with the modifier, 2 of them being essential for activity. Dialdehyde-ADP behaves as an affinity label of rabbit muscle pyruvate kinase, the inactivator binds probably to lysine residues at or near the active site, forming morpholine-like structures; and the enzyme possesses 2 modifiable groups essential for activity, the reaction of one of them being sufficient to cause total loss of activity.
dc.fuente.origenWOS
dc.identifier.issn0006-3002
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/99926
dc.identifier.wosidWOS:A1982NT39000001
dc.issue.numero2
dc.language.isoen
dc.pagina.final185
dc.pagina.inicio177
dc.revistaBiochimica et biophysica acta
dc.rightsacceso restringido
dc.subject.ods03 Good Health and Well-being
dc.subject.odspa03 Salud y bienestar
dc.titleAFFINITY LABELING OF RABBIT MUSCLE PYRUVATE-KINASE WITH DIALDEHYDE-ADP
dc.typeartículo
dc.volumen704
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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