EMULSIFYING FUNCTION OF LACTOPHORIN AND CONDUCTION OF INHIBITION OF LIPOPROTEIN LIPASE

乳激素的乳化作用及其对脂蛋白脂肪酶的抑制作用

• 批准号: 03660291
• 负责人: KANNO Choemon
• 金额: $ 1.28万
• 依托单位: UTSUNOMIYA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03660291/
• 关键词: BOVINE MILK; LACTOPHORIN; LIPOPROTEIN LIPASE; EMULSIFYING FUNCTION; INHIBITION OF LIPOLYSIS; RANCID FLAVOR; PROTEOSE PEPTONE; MILK FAT GLOBULE MEMBRANE; 乳化; リポプロテインリパ-ゼ; リポリシス; リパ-ゼ; 乳化安定性

Lactophorin (LP) reacts with the antibody of soluble glycoprotein from bovine milk fat globule membrane and present as the major glycoprotein in the component-3 of proteose peptone fraction of milk whey. LP is rich in hydrophobic amino acid residues and possesses saccharide chain which protect coalescence and agglutination of fat globules. In the present study, it has been undertaken to study the emulsifying ability of LP and inhibition of lipoprotein lipase by LP.1. Emulsifying function Emulsifying ability was evaluated by measuring emulsifying activity, emulsion stability, viscosity, diameter, and specific surface area of globules in emulsion which was prepared by homogenizing a mixture of 1% protein including LP and 25% milk fat in 0.1 M phosphate buffer (pH 7.0) on a Polytron homogenizer (19,500 rpm) at 45ﾟC. 1) LP formed emulsion with higher emulsifying ability at short emulsifying time (30 sec)and 40 mg LP per g of milk fat. 2) Increasing LP concentration, emulsifying properties … More increased. However, viscosity of emulsion increased. 3) LP formed oil in water emulsion in the range of 10 and 50% milk fat in the level of 40 mg of LP per g fat. 4) Emulsifying ability was influenced by pH; emulsion stability was lowest at pH 4, which in isoelectric point of LP, but high at pH 7-10.5) LP consists of mostly 28 and 18 KDa polypeptides. Major polypeptide adsorbed on the surface of globules in emulsion prepared at pH 7 was 28 KDa and both in emulsion at pH 3, 4, and 9.2. Inhibition of lipoprotein lipase (LPL) LPL is contained indigenously in fresh bovine milk, but not act on milk fat in the globule which is enveloped with fat globule membrane. However, partially destructed fat globules are easily hydrolyzed by LPL. In this study. indigenous LPL in sonicated milk was utilized for examining the inhibitory action of LP to LPL. 1) Lipolysis in fresh bovine milk was accelerated by sonic treatment. 2) Of proteose-peptone fractions, component-3 fraction enriched in LP showed the inhibitory effect on LPL;LP in 40 mg LP per ml of sonicated milk inhibited about 30% of the release of fatty acid. 3) LP was purified by gel filtration of component-3 fraction. Inhibition to LPL in sonicated milk increased with the increase of purified LP concentration. LP in 40 mg/ml of sonicated milk inhibited about 80% of the release of fatty acid by LPL for 60 min. at 37ﾟC. Less

乳蛋白与牛乳脂肪球膜可溶性糖蛋白抗体发生反应，作为主要糖蛋白存在于乳清蛋白蛋白胨组分-3中。LP含有丰富的疏水氨基酸残基，并具有保护脂肪球聚结和凝集的糖链。在本研究中，研究了LP的乳化能力和LP.1对脂蛋白脂肪酶的抑制作用。将含有1%蛋白（LP）和25%乳脂)的乳浊液加入0.1 M磷酸盐缓冲液（pH 7.0），在Polytron均质机（19500 rpm）上，在45℃的温度下均质，通过测量乳浊液的乳化活性、乳化稳定性、粘度、粒径和比表面积来评价乳化能力。1) LP在较短的乳化时间（30秒）和40 mg / g乳脂下形成乳化能力较高的乳化液。2) LP浓度增加，乳化性能增加。然而，乳液粘度增加。3)在每g脂肪中添加40 mg LP的水平下，乳脂含量在10% ~ 50%范围内形成乳脂水乳状油。4) pH对乳化能力有影响；pH值为4时乳化液稳定性最低，pH值为7 ~ 10.5时乳化液稳定性较高。在pH为7时制备的乳液中，吸附在微球表面的主要多肽为28 KDa，在pH为3、4和9.2时制备的乳液中，吸附在微球表面的多肽均为28 KDa。脂蛋白脂肪酶（LPL）的抑制作用鲜牛乳中含有脂蛋白脂肪酶，但不作用于被脂肪球膜包裹的乳脂球中的脂肪。然而，部分破坏的脂肪球很容易被LPL水解。在这项研究中。利用超声波牛奶中的天然LPL，考察了LP对LPL的抑制作用。1)超声处理可加速鲜牛乳中的脂肪分解。2)在蛋白酶-蛋白胨组分中，富含LP的组分-3组分对LPL有抑制作用；每毫升超声波牛奶中含有40 mg LP的LP可抑制约30%的脂肪酸释放。3)用凝胶过滤组分3分离纯化LP。超声乳对LPL的抑制作用随着纯化LP浓度的增加而增强。40 mg/ml超声乳中的LP在37ºC条件下抑制LPL释放约80%的脂肪酸。少