hydrolysis, using water to break the C-N bond of the amino group attached to 5'-AMP. This results in binding 5'-IMP is then catalyzed by Inosine-5'-monophosphate dehydrogenase (IMPDH), facilitating guanine nucleotide biosynthesis. The initial step of AMP degradation is the conversion to xanthine into alternative routes, xanthosine or hypoxanthine. Crystal Structure Molecular weight of adenosine-phosphate deaminase is 30000-60000 Da or 15223 Da. The number of amino acid sequences is 135. There are 0 transmembrane helices. Active Site The turnover number for adenosine-phosphate deaminase is 690 ATP, 630 ADP, and 710 AMP. The km value is 0.047 for 5'-AMP. the pH optimum is 6.0-6.8 for 5'-AMP, however the pH range is 4-8 with a temperature optimum of 55 °C. Natural substrates for this enzyme are 5'-AMP and H2O. The substrate spectrum is as follows: Adenosine + H2O Adenosine phosphates + H2O NAD+ + H2O dATP + H2O dADP + H2O dAMP + H2O Deoxyadenosine + H2O The product spectrum is as follows: Inosine + NH3 Inosine phosphates + NH3 Nicotinamide-hypoxanthine-dinucleotide + NH3 dITP + NH3 dIDP + NH3 dIMP + NH3 Deoxyinosine + NH3 References Further reading EC 3.5.4 Enzymes of unknown structure