Field R B, Scow R O
J Biol Chem. 1983 Dec 10;258(23):14563-9.
Lingual lipase was highly purified from serous glands of rat tongue. Protein containing lipolytic activity was precipitated with 30-60% saturated ammonium sulfate from the 100,000 X g supernatant of a homogenate of the glands, resuspended in buffered solution, treated and precipitated with acetone at -20 degrees C, and redissolved in buffered solution at pH 5.4. This protein was further purified by hydrophobic chromatography on ethyl agarose; it was eluted with a micellar solution of sodium taurodeoxycholate, oleic acid, and monooleoylglycerol at pH 6.3. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed this fraction consisted of one major protein band, with Mr = 51,000, and several minor bands. A similar value for Mr of protein with lipolytic activity was obtained when acetone-precipitated protein was subjected to gel filtration on Sephadex G-200 indicating that 51,000 is the Mr of an active form of lingual lipase. Lingual lipase purified from rat tongue had a specific activity of 230 units/mg of protein (unit = micromoles of fatty acid formed/min at 37 degrees C). Purified lingual lipase hydrolyzed immediately long chain triacylglycerol to diacylglycerol and fatty acid in medium containing 17 mM sodium taurodeoxycholate and 3.3 mM CaCl2 at pH 5.4. It then hydrolyzed diacylglycerol, and later monoacylglycerol, but at rates 1:6 and 1:20, respectively, of that for triacylglycerol. The activity of lingual lipase in the presence of sodium taurodeoxycholate and CaCl2 was decreased only 33% when pH of the incubation medium was increased to 6.5. This indicates that lingual lipase, which is known to be active in stomach, could act in the small intestines.
舌脂肪酶是从大鼠舌的浆液腺中高度纯化得到的。将含有脂解活性的蛋白质从腺体匀浆100,000×g上清液中用30 - 60%饱和度的硫酸铵沉淀，重悬于缓冲溶液中，在-20℃用丙酮处理并沉淀，然后在pH 5.4的缓冲溶液中重新溶解。该蛋白质通过在乙基琼脂糖上进行疏水层析进一步纯化；在pH 6.3时用牛磺脱氧胆酸钠、油酸和单油酸甘油酯的胶束溶液洗脱。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析表明，该级分由一条主要蛋白带（Mr = 51,000）和几条次要带组成。当丙酮沉淀的蛋白质在Sephadex G - 200上进行凝胶过滤时，得到了具有脂解活性的蛋白质的类似Mr值，表明51,000是舌脂肪酶活性形式的Mr。从大鼠舌中纯化的舌脂肪酶的比活性为230单位/毫克蛋白质（单位 = 37℃下每分钟形成的脂肪酸微摩尔数）。纯化的舌脂肪酶在含有17 mM牛磺脱氧胆酸钠和3.3 mM氯化钙、pH 5.4的介质中立即将长链三酰甘油水解为二酰甘油和脂肪酸。然后它水解二酰甘油，随后水解单酰甘油，但水解速率分别为三酰甘油的1/6和1/20。当孵育介质的pH值增加到6.5时，在牛磺脱氧胆酸钠和氯化钙存在下舌脂肪酶的活性仅降低33%。这表明已知在胃中具有活性的舌脂肪酶也可以在小肠中起作用。
