A Novel Alkaline Phosphatase/Phosphodiesterase, CamPhoD, from Marine Bacterium Cobetia amphilecti KMM 296

摘要: A novel extracellular alkaline phosphatase/phosphodiesterase from the structural protein family PhoD that encoded by genome sequence of marine bacterium Cobetia amphilecti KMM 296 (CamPhoD) has been expressed in Escherichia coli cells. The calculated molecular weight, number amino acids, and isoelectric point (pI) mature protein's subunit are equal to 54832.98 Da, 492, 5.08, respectively. salt-tolerant, bimetal-dependent enzyme CamPhoD a weight approximately 110 kDa its native state. is activated Co2+, Mg2+, Ca2+, or Fe3+ at concentration 2 mM exhibits maximum activity presence both Co2+ ions incubation medium pH 9.2. exogenous ions, such as Zn2+, Cu2+, Mn2+, well chelating agents EDTA EGTA, do not have an appreciable effect on activity. temperature optimum for 45 °C. catalyzes cleavage phosphate mono- diester bonds nucleotides, releasing inorganic phosphorus p-nitrophenyl (pNPP) guanosine 5'-triphosphate (GTP), determined Chen method, with rate 150- 250-fold higher than those bis-pNPP 5'-pNP-TMP, Michaelis-Menten constant (Km), Vmax, efficiency (kcat/Km) were 4.2 mM, 0.203 mM/min, 7988.6 S-1/mM; 6.71 0.023 1133.0 S-1/mM pNPP chromogenic substrates, Among 3D structures currently available, this study we found only low identical structure Bacillus subtilis homologous template modeling CamPhoD, new architecture phosphatase active site containing two Ca2+ ions. It evident bacterial phosphatase/phosphidiesterase member family.