Heat-labile bacterial alkaline phosphatase from a marine Vibrio sp

• Published in: Enzyme and microbial technology Vol. 27; no. 1; pp. 66 - 73
• Main Authors: Hauksson, Jónas B., Andrésson, Ólafur S., Ásgeirsson, Bjarni
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.07.2000; Elsevier Science
• Subjects: Affinity chromatography; Alkaline phosphatase; Bacteria; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; Cell culture; Cold-adaptation; Escherichia coli; Fundamental and applied biological sciences. Psychology; Marine bacterium; Marine biology; Miscellaneous; Mission oriented research; Psychrophilic; Purification; RNA; rRNA 16S; Stability; Thermodynamic stability; Vibrio; Vibrio sp; Marine bacterium; Alkaline phosphatase; Psychrophilic; Vibrio sp; Stability; Cold-adaptation; Purification; Cold; Enzyme; Phosphoric monoester hydrolases; Environmental factor; Esterases; Thermal stability; Marine environment; Enzymatic activity; Psychrophily; Bacteria; Hydrolases; Vibrionaceae; Physicochemical properties; Adaptation; Low temperature; Vibrio
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/S0141-0229(00)00152-6

Psychrophilic organisms have successfully adapted to various low-temperature environments such as cold ocean waters. Catalysts with increased catalytic efficiencies are produced, generally at the expense of thermal stability due to fewer non-covalent stabilizing interactions. A marine bacterial strain producing a particularly heat-labile alkaline phosphatase was selected from a total of 232 strains isolated from North-Atlantic coastal waters. From partial 16S rRNA sequences the strain was characterized as a Vibrio sp. An alkaline phosphatase was purified 151-fold with 54% yield from the culture medium using a single step affinity chromatography procedure on agarose-linked l-histidyldiazobenzylphosphonic acid. The active enzyme was a 55 ± 6 kDa monomer. The enzyme had optimal activity at pH 10 and was strikingly heat-labile with a half-life of 6 min at 40°C and 30 min at 32°C. This enzyme from Vibrio sp. had a higher turnover number (k cat) and higher apparent Michaelis–Menten factor (K m ) than the enzyme from Escherichia coli, a clear-indication of cold-adaptation. Inorganic phosphate was a competitive inhibitor with a relatively high K i value of 1.7 mM. Low affinity for phosphate may contribute to higher turnover rates due to more facile release of product.