A synthetic peptide substrate for initiation factor-2 kinases.
A peptide P(45-56) corresponding to residues 45-56 (sequence: ILLSELSRRRIR) of eIF-2 alpha was synthesised. It was phosphorylated by both of the well characterised eIF-2 alpha kinases viz.; the heme-controlled repressor (HCR) and the double stranded RNA-dependent inhibitor (dsI). Of four other protein kinases tested only protein kinase C (PKC) phosphorylated P(45-56), with complete dependence on phosphatidylserine. Only the residue corresponding to serine-51 in eIF-2 alpha was phosphorylated by HCR, dsI or PKC. The phosphorylation of the peptide by dsI and the phosphorylation of eIF-2 alpha by dsI or HCR showed sigmoidal kinetics with respect to substrate concentration.
Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K.
H
H
Mellor
C G
CG
Proud
D000595:Amino Acid Sequence; D000818:Animals; D007700:Kinetics; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000378:metabolism; D010748:Phosphopeptides / Q000302:isolation & purification; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D011817:Rabbits; D012156:Reticulocytes / Q000201:enzymology; D013379:Substrate Specificity; D019892:eIF-2 Kinase
D009842:Oligopeptides; D010748:Phosphopeptides; D011494:Protein Kinases; D019892:eIF-2 Kinase