N-Terminal sequence of creatine kinase from skeletal muscle of rabbit and rhesus monkey

Abstract

The first 20 amino acids from the N-terminus of skeletal muscle (MM) creatine kinase from both rabbit and rhesus monkey have been identified and these sequences show considerable homology. Contrary to an earlier report, the N-terminus was not found to be blocked. Both of these sequences show much less homology with the N-terminal sequence of heart muscle (MM) creatine kinase and no homology with that of the heart muscle mitochondrial (MiMi) isozyme. No homology was found between the N-terminal sequence of the mitochondrial isozyme and the URF (unidentified reading frame) proteins of the human mitochondrial genome, indicating that the mitochondrial enzyme is encoded by nuclear genes. This suggests the possibility that an N-terminal peptide may be cleaved from the mitochondrial isozyme on its translocation across the mitochondrial membrane.

Intracellular targeting of isoproteins in muscle cytoarchitecture.

“…From these experiments it is evident that even after injection of relatively high amounts of additional mRNA (up to 1,000 molecules per cell) no interaction of B-CK with the M-band was found. Thus B-CK appears to be unable to interact with the myofibrillar M-band and increased concentration of the protein No background of the rabbit reticulocyte translation system was observed during the exposure times used which were 16 h for lanes [3][4][5][6] and 64 h for lanes [7][8][9][10]. The minor bands observed in lanes 4-6 and 8-10 are most probably due to initiation of translation at internal methionines.…”