Sulfated lipids as inhibitors of pancreatic trypsin and chymotrypsin in epithelium of the mammalian digestive tract.
Sulfated lipids as inhibitors of pancreatic trypsin and chymotrypsin in epithelium of the mammalian digestive tract.
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硫酸化脂质作为哺乳动物消化道上皮中胰腺胰蛋白酶和糜蛋白酶的抑制剂。
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
N. Ito
中科院分区：
文献类型：
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作者：
M. Iwamori;Y. Iwamori;N. Ito
哺乳动物消化道上皮细胞中普遍存在的胆固醇硫酸盐和I_3SO_3-GalCer对胰蛋白酶和胰凝乳蛋白酶等典型消化酶的活性有抑制作用，而甾体硫酸盐、神经节苷脂等膜成分则无抑制作用。胰蛋白酶与I_3SO_3-GalCer在37 ℃预孵育10 min对胰蛋白酶的抑制作用是必需的，而胆固醇硫酸盐则不经预孵育就显示出抑制作用。硫酸化脂质处理的酶得到相同的Km和低于原始酶的Vmax。此外，这两种硫酸化脂质抑制链霉蛋白酶从灰色链霉菌，但不是赖氨酰内肽酶从无色杆菌。这些发现表明，胆固醇硫酸盐和I3 SO 3-GalCer在消化道中作为上皮抑制剂发挥作用，以防止内源性和外源性蛋白酶引起的组织损伤。
Cholesterol sulfate and I3SO3-GalCer, which were commonly contained in the epithelia of mammalian digestive tracts, were found to inhibit the activities of typical digestive enzymes, pancreatic trypsin and chymotrypsin, but steroid sulfates, gangliosides and the other membrane constituents did not show any inhibitory activity. The preincubation of trypsin with I3SO3-GalCer at 37 degrees C for 10min was necessary to inhibit the activity of trypsin, but cholesterol sulfate showed its inhibitory activity without preincubation. Sulfated lipid-treated enzyme gave the same Km as and lower Vmax than those of the original enzymes. Also, both sulfated lipids inhibited pronase from Streptomyces griseus, but not lysyl endopeptidase from Achromobacter lyticus. These findings indicate that cholesterol sulfate and I3SO3-GalCer in the digestive tract function as epithelial inhibitors to prevent tissue injury by endogenous and exogenous proteases.