Facchiano A, Cordella-Miele E, Miele L, Mukherjee A B
Section on Developmental Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.
Life Sci. 1991;48(5):453-64. doi: 10.1016/0024-3205(91)90501-2.
We investigated the possible mechanism of inhibition of porcine pancreatic phospholipase A2 in vitro by rabbit uteroglobin and by the antiflammin peptides. We optimized the conditions of phospholipase A2 assay using a deoxycholate-phosphatidylcholine mixed micellar substrate and established the activity of these inhibitors under optimized conditions. The results of fluorescence studies and crosslinking experiments indicate that the inhibitors interact with the enzyme in solution and affect the increase in intrinsic fluorescence of phospholipase A2 observed upon interaction with a mixed micellar substrate. In addition, we identified a sequence similarity between the antiflammin peptides, the putative active region of uteroglobin and a region in pancreatic phospholipase A2. This region of phospholipase A2 has been previously identified as being involved in the regulation of dimerization of this enzyme, and is conserved in the pancreatic-type enzymes. Taken together, these observations suggest that uteroglobin and antiflammins interact with porcine pancreatic phospholipase A2 and this may, at least in part, explain the enzyme inhibitory effect of these molecules observed in vitro. One possible mechanism of this effect may be an interference with the dimerization process of phospholipase A2 which is associated with interfacial activation.
我们研究了兔子宫珠蛋白和抗炎症肽在体外抑制猪胰磷脂酶A2的可能机制。我们使用脱氧胆酸盐 - 磷脂酰胆碱混合胶束底物优化了磷脂酶A2测定的条件，并在优化条件下确定了这些抑制剂的活性。荧光研究和交联实验结果表明，抑制剂在溶液中与酶相互作用，并影响磷脂酶A2与混合胶束底物相互作用时观察到的内在荧光增加。此外，我们鉴定出抗炎症肽、子宫珠蛋白的推定活性区域与胰磷脂酶A2中的一个区域之间存在序列相似性。磷脂酶A2的这个区域先前已被确定参与该酶的二聚化调节，并且在胰腺型酶中是保守的。综上所述，这些观察结果表明，子宫珠蛋白和抗炎症肽与猪胰磷脂酶A2相互作用，这可能至少部分解释了在体外观察到的这些分子对该酶的抑制作用。这种作用的一种可能机制可能是干扰与界面激活相关的磷脂酶A2的二聚化过程。
