as an extension of our previous reports that cardiac and skeletal muscle troponin i ( tn-i ) and troponin t ( tn-t ) are excellent substrates for protein kinase c ( pkc ) ( katoh , n. , wise , b. c. , and kuo , j. f. ( 1983 ) biochem . j . 209 , 189-195 ; mazzei , g. j. , and kuo , j. f. ( 1984 ) biochem . j . 218 , 361-369 ) , we have now determined that pkc phosphorylated serine 43 ( and/or serine 45 ) , serine 78 , and threonine 144 in the free tn-i subunit and threonine 190 , threonine 199 , and threonine 280 in the free tn-t subunit of bovine cardiac troponin .
C0077401
tn-i
C0041199
tn-t