title: Demonstration of two protein kinases in extracts of Legionella micdadei.
abstract: Protein kinases I (PK I) and II (PK II) were purified 253- and 13.5-fold, respectively, from an extract of sonically disrupted cells of Legionella micdadei by ion-exchange chromatography on QAE-Sephadex, by histone affinity chromatography, and by HPLC-gel filtration chromatography. Both enzymes catalysed the phosphorylation of calf thymus histones, with a Km of 2.7 mg ml-1 for PK I and 2.9 mg ml-1 for PK II. Histone H2b was the best protein kinase substrate for both PK I and PK II. The pH optima were 6.8 and 7.0 for PK I and PK II respectively. The Km for ATP was 0.29 mM for PK I and 0.33 mM for PK II. PK II activity was stimulated by either cAMP or cGMP, whereas PK I was inhibited by both cyclic nucleotides. The activity of PK I was unaffected by addition of calmodulin, diacylglycerol and mixtures of Ca2+ and acidic phospholipids, but these additions increased PK II activity threefold. The activity of PK II was stimulated by spermine and spermidine, but PK I was inhibited by these compounds. PK I and PK II were both strongly inhibited by heparin.
authors.affiliation: Department of Microbiology, Biochemistry and Molecular Biology, University of Pittsburgh School of Medicine, PA 15261.
authors.forename: A K
authors.initials: AK
authors.lastname: Saha
authors.forename: J N
authors.initials: JN
authors.lastname: Dowling
authors.forename: N K
authors.initials: NK
authors.lastname: Mukhopadhyay
authors.forename: R H
authors.initials: RH
authors.lastname: Glew
mesh_terms: D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D000242:Cyclic AMP / Q000494:pharmacology; D006152:Cyclic GMP / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007875:Legionella / Q000201:enzymology*; D011494:Protein Kinases / Q000302:isolation & purification* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D000242:Cyclic AMP; D011494:Protein Kinases; D006152:Cyclic GMP