THE AMINO-ACID-SEQUENCES OF HUMAN AND PIG L-ARGININE-GLYCINE AMIDINOTRANSFERASE

We have isolated and sequenced the L-arginine:glycine amidinotransferase of pig kidney mitochondria. Due to endogenous proteolysis, the purified molecules showed some heterogeneity at the N terminus. The longest form recovered had 386 amino acids. Part of the pig amidinotransferase sequence information was used to isolate cDNA clones coding for the human enzyme. The deduced amino acid of the human amidinotransferase was 37 amino acids longer due to the presence of a signal sequence. The mature proteins were 94% identical to each other and 36% identical to the sequences of bacterial L-arginine:inosamine phosphate amidinotransferases.