Extracellular proteases from 8 Antarctic psychrotolerant Pseudomonas sp. strains were purified and characterised. All of them are neutral metalloproteases, have an apparent molecular mass of 45kDa, optimal activity at 40 degrees C and pH 7-9, retaining significant activity at pH 5-11. With the exception of P96-18, which is less stable, all retain more than 50% activity after 3 h of incubation at pH 5-9 and show low thermal stability (their half-life times range from 20 to 60 min at 40 degrees C and less than 5 min at 50 degrees C). These proteases can be used in commercial processes carried out at neutral pH and moderate temperatures, and are of special interest for their application in mixtures of enzymes where final thermal selective inactivation is needed. Results also highlight the relevance of Antarctic biotopes for the isolation of protease-producing enzymes active at low temperatures.

中文翻译：

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来自八种抗精神病性南极菌株的细胞外蛋白酶。

来自8个南极精神耐受性假单胞菌（Pseudomonas sp。）的细胞外蛋白酶。菌株被纯化并鉴定。它们都是中性金属蛋白酶，具有45kDa的表观分子量，在40℃和pH 7-9下的最佳活性，在pH 5-11下保持显着的活性。除了稳定性较差的P96-18外，在pH 5-9下孵育3小时后，所有P96-18均保留超过50％的活性，并且显示出较低的热稳定性（它们的半衰期在40度下为20至60分钟C，并在50摄氏度下少于5分钟）。这些蛋白酶可用于在中性pH和中等温度下进行的商业过程中，并且特别需要将它们用于需要最终热选择性灭活的酶混合物中。