Nature of the inhibitory effect of collagenase on phosphodiesterase activity.
Nature of the inhibitory effect of collagenase on phosphodiesterase activity.
复制标题
胶原酶对磷酸二酯酶活性的抑制作用的性质。
作者：
P. Engfeldt;P. Arner;J. Ostman
磷酸二酯酶（PDE）活性水平在胶原酶分离的人脂肪细胞中比在脂肪组织碎片中低。这种抑制作用不是种属特异性的，因为胶原酶也抑制大鼠脂肪组织和牛心脏中的PDE。在分离的脂肪细胞的亚细胞组分中，PDE活性在质膜富集组分中最低，在胞质组分中最高。这与从脂肪组织碎片获得的亚细胞级分中的PDE相反。在剂量反应实验中，胶原酶抑制颗粒PDE的程度远大于其抑制可溶性PDE的程度。胶原酶可完全消除PDE的胞外活性。反复洗涤或再孵育分离的脂肪细胞没有恢复PDE活性。具有低比蛋白酶活性的纯化的胶原酶在分离的脂肪细胞中降低PDE活性的程度小于具有高比蛋白酶活性的胶原酶。胶原蛋白和几种蛋白酶抑制剂在防止暴露于胶原酶后PDE减少方面无效。它的结论是，用于脂肪细胞分离的胶原酶制剂中的非特异性蛋白酶与颗粒和可溶性PDE相互作用，导致在分离的脂肪细胞中PDE活性的不可逆抑制。在各种形式的PDE中，质膜相关PDE似乎对胶原酶最敏感。
The level of phosphodiesterase (PDE) activity is lower in collagenase-isolated human fat cells than in adipose tissue fragments. The inhibition is not species-specific since collagenase also inhibits PDE in rat adipose tissue and bovine heart. In subcellular fractions from isolated fat cells, the PDE activities were lowest in the plasma membrane-enriched fractions and highest in the cytosolic fractions. This is opposite to PDE in subcellular fractions obtained from adipose tissue fragments. In dose-response experiments, collagenase inhibited particulate PDE to a much larger extent than it inhibited soluble PDE. The extracellular activities of PDE were completely eliminated by collagenase. Repeated washings or reincubation of the isolated fat cells did not restore the PDE activity. A purified collagenase with low specific protease activity reduced the PDE activity in isolated fat cells to a lesser extent than did a collagenase with high specific protease activities. Collagen and several protease inhibitors were ineffective in preventing the reduction of PDE after exposure to collagenase. It is concluded that nonspecific proteases in the collagenase preparations used for fat cell isolation interact with particulate and soluble PDE causing an irreversible inhibition of PDE activity in isolated fat cells. Of the various forms of PDE, plasma membrane-associated PDE seems most sensitive to collagenase.