Nakatsukasa H
Acta Med Okayama. 1986 Apr;40(2):83-91. doi: 10.18926/AMO/31921.
Type IV collagen-degrading enzyme activity was measured in liver homogenate obtained from 10 patients with hepatocellular carcinomas. Type IV collagen, the enzyme substrate, was extracted from human placenta with pepsin digestion, and labeled with [1-14C] acetic anhydride. The homogenate was preincubated with p-aminophenylmercuric acetate to activate the latent form of the enzyme, and then the enzyme activity was measured at pH 7.5 by adding a substrate mixture. Referring to previous reports, the enzyme measured seemed to be a neutral metalloprotease. The enzyme activity of the homogenate was markedly reduced by omitting the p-aminophenylmercuric acetate pretreatment, indicating that the enzyme was present mainly in the latent form. The activity seemed to be higher in the peripheral portion of hepatocellular carcinoma than in the center. Further the activity was found to be the highest in a hepatocellular carcinoma patient with many metastatic nodules in the lung. The results might suggest that type IV collagen-degrading enzyme participates in tumor invasion and intrahepatic or remote metastasis.
在从10例肝细胞癌患者获取的肝脏匀浆中检测IV型胶原降解酶活性。IV型胶原作为酶的底物，通过胃蛋白酶消化从人胎盘中提取，并用[1-¹⁴C]乙酸酐进行标记。将匀浆与对氨基苯基汞乙酸盐预孵育以激活酶的潜在形式，然后通过加入底物混合物在pH 7.5下测量酶活性。参考先前的报道，所检测的酶似乎是一种中性金属蛋白酶。省略对氨基苯基汞乙酸盐预处理后，匀浆的酶活性显著降低，表明该酶主要以潜在形式存在。在肝细胞癌的周边部分，该活性似乎高于中心部分。此外，在一名肺部有许多转移结节的肝细胞癌患者中发现该活性最高。这些结果可能提示IV型胶原降解酶参与肿瘤侵袭以及肝内或远处转移。
