ABSTRACT
Chemical modification of tryptophanyl residues of NADPH - adrenodoxin reductase by N - bromosuccinimide and trichloroethanol prevents the interaction of the enzyme with adrenodoxin. The modification does not touch other amino acid residues besides tryptophan (tyrosine, lysine and cysteine) or disturb the structure of protein. The presence of adrenodoxin suppresses the modification. The data obtained indicate the participation of adrenodoxin reductase tryptophan residues in the interaction with adrenodoxin.
Subject(s)
Adrenodoxin/metabolism , Ferredoxin-NADP Reductase/metabolism , Tryptophan/chemistry , Adrenal Cortex/enzymology , Bromosuccinimide/metabolism , Cytochrome c Group/metabolism , Electron Transport , Ethylene Chlorohydrin/analogs & derivatives , Ethylene Chlorohydrin/metabolism , Ferredoxin-NADP Reductase/antagonists & inhibitors , Oxidation-Reduction , SpectrophotometryABSTRACT
Protein kinase C catalyzes phosphorylation of the rat skeletal muscle AMP-deaminase in the presence of calcium ions and phosphatidylserine. At the same time, the catalytic subunit of cAMP-dependent protein kinase fails to phosphorylate AMP-deaminase. Ca2+, phosphatidylserine-dependent phosphorylation decreases three-fold (from 0.6 to 0.2 mM) the Km value and does not affect Vmax. Protein kinase C-induced phosphorylation of AMP-deaminase, besides ADP-ribosylation, is suggested to be involved in regulating the AMP-deaminase activity in vivo.
Subject(s)
AMP Deaminase/metabolism , Brain/enzymology , Muscles/enzymology , Nucleotide Deaminases/metabolism , Protein Kinase C/metabolism , AMP Deaminase/isolation & purification , Animals , Humans , Kinetics , Molecular Weight , Phosphorylation , Protein Kinase C/isolation & purification , RatsABSTRACT
AMP-deaminase from rat skeletal muscle was purified by affinity chromatography on phosphocellulose and gel-filtration on Sephadex G-200. It was established that disulfide bridges and hydrogen bonds were not essential for stability of enzyme oligomeric structure. The dimeric structure of enzyme subunit with Mr 76 kDa (S1) was detected by means of PAGE in the presence of SDS: besides the S1 there were also exhibited two additional bands with Mr 42 (S2) and 33 (S3) kDa. Repeated SDS-PAGE of S1 has revealed the same three protein bands. These results indicate the possibility of dissociation of S1-subunit into two subunits with close Mr values.
