title: Solubilization of rat heart sarcolemma 5'-nucleotidase by phosphatidylinositol-specific phospholipase C.
abstract: The influence of a phosphatidylinositol-specific phospholipase C treatment on rat heart sarcolemmal 5'-nucleotidase was investigated. Upon complete hydrolysis of all phosphatidylinositol in the sarcolemma, 75% of 5'-nucleotidase activity was found in the solubilized form. The insolubilized enzyme after this treatment has the same Km for AMP as the untreated, sarcolemmal-bound enzyme (0.04 mM), whereas the solubilized enzyme has a 40-fold increase in Km for AMP (0.16 mM). Other sarcolemmal-bound enzymes were not affected by the same treatment. Hence, the specific involvement of phosphatidylinositol in the binding of 5'-nucleotidase to the sarcolemma of the rat heart is clearly demonstrated.
mesh_terms: D015720:5'-Nucleotidase; D000818:Animals; D007700:Kinetics; D008563:Membrane Lipids; D009206:Myocardium / Q000201:enzymology*; D009708:Nucleotidases / Q000302:isolation & purification* / Q000378:metabolism; D010716:Phosphatidylinositols; D010740:Phospholipases / Q000378:metabolism*; D051381:Rats; D012508:Sarcolemma / Q000201:enzymology*; D012995:Solubility; D013379:Substrate Specificity; D010738:Type C Phospholipases / Q000378:metabolism*
chemical_list: D008563:Membrane Lipids; D010716:Phosphatidylinositols; D010740:Phospholipases; D009708:Nucleotidases; D015720:5'-Nucleotidase; D010738:Type C Phospholipases