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PubMed · 444542

Phosphorylase kinase from human polymorphonuclear leukocytes.

N B Sørensen
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Abstract

Phosphorylase kinase from human polymorphonuclear leukocytes was investigated in a gel filtered crude preparation (17,000 x g supernatant). It was found to exist in two forms, one (the phosphorylated form) more active than the other (the dephosphorylated form). Interconversion between the two forms was carried out by a cyclic AMP dependent protein kinase and phosphoprotein phosphatase, respectively. The ratio of activity measured at pH 8.0 and 6.0 was 0.36 for the non-activated and 0.83 for the activated form, which is in contrast to the behaviour of phosphorylase kinase from muscle. Km app for the substrate phosphorylase b was 650 U/ml and 85 U/ml for the non-activated and activated form, respectively, whereas Km app for ATP was 0.03 mM and identical for the two forms. The non-activated form of phosphorylase kinase was activated by Ca2+ in the range 10(-7)--5 . 10(-6) M, which may have physiological importance, whereas the activated form was insensitive to variations in Ca2+ concentration between 10(-9) and 10(-3) M.

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CalciumEnzyme ActivationHumansIsoenzymesKineticsNeutrophilsPhosphorylase KinasePhosphorylase bTrypsinJournal Article

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N B Sørensen. 1979-05-10. Phosphorylase kinase from human polymorphonuclear leukocytes.. https://doi.org/10.1016/0005-2744(79)90288-2

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