both the methionine and cysteine residues must be removed from the nh2 terminus of the intermediate to yield the mature form of smooth muscle alpha- isoactin . the removal of the cysteine residue in vivo is not direct but apparently involves acetylation of the cysteine and subsequent post-translational cleavage of the resulting acetylcysteine .
C0010654
cysteine
C0001047
acetylcysteine