O'Connor C J, Wallace R G
J Pediatr Gastroenterol Nutr. 1985 Jun;4(3):446-52. doi: 10.1097/00005176-198506000-00021.
The hydrolysis of a series of n-alkyl esters of 4-nitrobenzoic acid, and of isopropyl 4-nitrobenzoate, 4'-nitrophenyl 4-nitrobenzoate, and 4-nitrobenzoyl 1-monoglycerol, catalyzed by human milk lipase in the absence and presence of cholate stimulation, has been measured at pH 7.3, 37.5 degrees C. It has been shown that the enzyme possesses a specific alkyl binding site which is hydrophobic in nature and wide enough to accommodate two fatty acid chains lying side by side or a phenyl ring lying flat. The hydrophobic nature of this site is affected by bile salt stimulation of the enzyme. Hydrophobicity parameters have been calculated for hydrocarbon chains lying in the acyl and alkyl binding sites of human milk lipase. A mechanism is suggested for the role of bile salts in stimulating the enzyme in its activity against water soluble esters and water soluble triacylglycerols.
在有无胆酸盐刺激的情况下，于pH 7.3、37.5℃条件下测定了人乳脂肪酶催化的一系列4 - 硝基苯甲酸正烷基酯、4 - 硝基苯甲酸异丙酯、4'- 硝基苯基4 - 硝基苯甲酸酯和4 - 硝基苯甲酰基1 - 甘油单酯的水解情况。结果表明，该酶具有一个特定的烷基结合位点，其本质为疏水性，宽度足以并排容纳两条脂肪酸链或平躺的苯环。该位点的疏水性受胆盐对酶的刺激影响。已计算出位于人乳脂肪酶酰基和烷基结合位点的烃链的疏水性参数。提出了一种关于胆盐在刺激该酶对水溶性酯和水溶性三酰甘油的活性中所起作用的机制。
