Pencreac'h G, Baratti J C.
Université de la Méditerranée, Faculté des Sciences de Luminy, Biocatalyse et Chimie Fine, CNRS UMR 6111, Marseille, France
Enzyme Microb Technol. 2001 Mar 8;28(4-5):473-479. doi: 10.1016/s0141-0229(00)00355-0.
The protein content and the rates of hydrolysis of p-nitrophenyl palmitate (pNPP) in water (soluble enzyme and emulsified substrate) and in heptane (soluble substrate and insoluble enzyme) were measured for thirty-two commercial lipase preparations. The protein content of the powders varied in a wide range as well as the activity on emulsified pNPP showing the high heterogeneity of the commercial samples. Activity in heptane also varied but to a lesser extent than that in water. There was no direct correlation between activities in water and in heptane as assayed with the same hydrolytic reaction. The ratio of activity in heptane to that in water, R(O/A) ratio, was introduced to characterize activity in organic media. Six lipases showed R(O/A) values higher than 1 demonstrating a higher activity in organic solvent than in water. A linear correlation of R(O/A) with activity in water (log plot) suggested the strong influence of diffusional limitations on activity of solid enzyme suspended in organic solvents.
对32种市售脂肪酶制剂测定了其蛋白质含量以及对棕榈酸对硝基苯酯（pNPP）在水（可溶性酶和乳化底物）和庚烷（可溶性底物和不溶性酶）中的水解速率。粉末状制剂的蛋白质含量变化范围很大，对乳化pNPP的活性也各不相同，表明市售样品具有高度异质性。在庚烷中的活性也有变化，但程度小于在水中的活性变化。对于相同的水解反应，在水和庚烷中的活性之间没有直接相关性。引入庚烷中活性与水中活性的比值，即R（O/A）比值，来表征在有机介质中的活性。六种脂肪酶的R（O/A）值高于1，表明其在有机溶剂中的活性高于在水中的活性。R（O/A）与水中活性的线性相关性（对数图）表明扩散限制对悬浮在有机溶剂中的固体酶活性有强烈影响。
