Cytosine deaminase: Structural modification studies

Summary Structural modification studies have shown that a cysteine, a histidine and possibly an arginine residue are involved in the catalytic process. The enzyme gave a single band on polyacrylamide gel electrophoresis, and the amino acid analysis showed it to contain a high proportion of hydrophobic residues, which was in agreement with the chemical modification results.Acknowledgment. We wish to thank Herts CC for a research assistantship (S.Y.) and SRC for a research fellowship (to M.J.G.)