title: Isolation and characterization of a phytase with improved properties from Citrobacter braakii.
abstract: Citrobacter braakii YH-15 produced an intracellular phytase which was purified 12800 fold to homogeneity with the specific activity of 3457 units mg(-1), which is 1.9 times higher than E. coli phytase previously recorded as having the highest specific activity. Its molecular weight was 47 kDa by SDS-PAGE gel. Enzyme activity was optimal at pH 4 and at 50 degrees C. The Km value for sodium phytate was 0.46 mM with a Vmax 6027 U mg(-1). The phytase was resistant to proteases such as trypsin, pepsin, papain, pancreatin, and elastase.
mesh_terms: D010832:6-Phytase / Q000096:biosynthesis* / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification; D000595:Amino Acid Sequence; D002954:Citrobacter / Q000737:chemistry / Q000145:classification / Q000201:enzymology* / Q000302:isolation & purification*; D004789:Enzyme Activation; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011522:Protons; D011786:Quality Control; D012623:Seawater / Q000382:microbiology*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D011522:Protons; D010832:6-Phytase