Proteinase K processing of rabbit muscle creatine kinase.
Proteinase K cleaves selectively both cytosolic and mitochondrial isoforms of creatine kinase leading to the appearance of two fragments, a large N-terminal one (K1) and a small C-terminal peptide (K2) which remain associated together. The loss of enzymatic activity correlates with the extent of monomer cleavage. N-terminal sequencing of the K2 fragments from rabbit cytosolic and pig mitochondrial creatine kinase shows that these peptides begin with A328 and A324, respectively. Electrospray ionization mass spectrometry demonstrates that K2 peptide is composed of 53 residues (A328-K380). However, the C-terminal end of the K1 fragment is not A327 as expected, but D325. Thus, the amino acids residues T326 and A327 have been eliminated by the protease.
Leydier
C
C
UPRESA 5013 Centre National de le Recherche Scientifique, Université Claude Bernard Lyon I, Villeurbanne, France.
Andersen
J S
JS
Couthon
F
F
Forest
E
E
Marcillat
O
O
Denoroy
L
L
Vial
C
C
Clottes
E
E
D000595:Amino Acid Sequence; D000818:Animals; D003402:Creatine Kinase / Q000737:chemistry / Q000378:metabolism*; D019286:Endopeptidase K / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D007527:Isoenzymes; D007700:Kinetics; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000201:enzymology*; D011817:Rabbits; D017421:Sequence Analysis; D013379:Substrate Specificity; D013552:Swine
D007527:Isoenzymes; D003402:Creatine Kinase; D019286:Endopeptidase K