360 MHz laser photo‐CIDNP of porcine pancreatic colipase A
360 MHz laser photo‐CIDNP of porcine pancreatic colipase A
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猪胰辅脂肪酶 A 的 360 MHz 激光 photo-CIDNP
DOI：
10.1016/0014-5793(80)80797-6
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发表时间：
1980
期刊：
影响因子：
3.5
通讯作者：
R. Kaptein
中科院分区：
文献类型：
--
作者：
P. Canioni;P. Cozzone;R. Kaptein
辅脂酶是在哺乳动物的胰腺分泌物中发现的低分子量（约11000）的蛋白质[11]。其生理作用是：（i）在高浓度胆汁盐存在下，允许脂肪酶吸附在脂-水界面，（ii）在表面能变化较大的情况下，使酶稳定在其完全活性形式[2-51]。辅脂酶在底物-水界面上的吸附现在被认为是脂解过程的第一步，它可能与辅蛋白表面上存在特定结构域有关[6]。对猪辅脂酶的质子NMR、荧光和分光光度研究表明，两个酪氨酸和一个组氨酸残基位于蛋白质的疏水区域中，其可能构成辅脂酶上的脂质结合位点的至少一部分[7- 111]。在这里，我们报告了一系列对猪辅脂酶A进行的激光光CIDNP实验[111]。光CIDNP方法基于染料与芳香族残基的可逆光反应中核自旋极化的产生[121]。当酪氨酸、组氨酸和色氨酸残基的侧链可接近光激发染料时，它们可被极化[13，14]。猪辅脂酶A含有3个酪氨酸、2个组氨酸和2个苯丙氨酸
Colipase is a protein of low molecular weight (about 11 000) found in the pancreatic secretion of mammals [11. Its physiological role is,(i) to allow lipase to adsorb at lipid-water interface in the presence of high concentrations of bile salts,(ii) to stabilize the enzyme in its fully active form under large variations of surface energy [2-51. The adsorption of colipase to the substrate-water interface is now accepted as the first step of the lipolytic process and it can be related to the presence of a particular domain on the surface of the coprotein [6]. Proton NMR, fluorescence and spectrophotometric studies on porcine colipase have indicated that two tyrosine and one histidine residues are located in a hydrophobic region of the protein that might constitute at least a part of the lipid binding site on colipase [7-l 11. Here we report a series of laser photo-CIDNP experiments performed on porcine colipase A [111. The photo-CIDNP method is based on the generation of nuclear spin polarization in a reversible photoreaction of a dye with aromatic residues [121. The sidechains of tyrosine, histidine and tryptophan residues can be polarized when they are accessible to the photo-excited dye [13, 14]. Porcine colipase A contains 3 tyrosine, 2 histidine and 2 phenylalanine