Baumann G
J Clin Endocrinol Metab. 1976 Jul;43(1):222-5. doi: 10.1210/jcem-43-1-222.
Human growth hormone B can be converted to its more acidic isohormones C, D, and E by limited enzymatic cleavage with purified plasmin in vitro. This process is accompanied by an increase of biological activity in the rat tibia line assay. A possible role of endogenous circulating plasmin in the in vivo formation of these isohormones was investigated. Human plasma, serum, glass-contact-activated serum, and serum extracts after the removal of protease inhibitors were incubated with ratioiodinated hGH-B and C for up to 24 h. Aliquots were analyzed at frequent intervals by polyacrylamide gel electrophoresis, followed by autoradiography and counting of radioactive bands. No evidence for interconversion or transformation to hGH-D and E was found. It is concluded that endogenous circulating plasmin does not play a major role in the conversion of hGH to its "activated" isohormones.
人生长激素B在体外经纯化的纤溶酶有限酶切可转化为酸性更强的同型激素C、D和E。此过程伴随着大鼠胫骨线试验中生物活性的增加。研究了内源性循环纤溶酶在这些同型激素体内形成过程中的可能作用。将人血浆、血清、玻璃接触激活血清以及去除蛋白酶抑制剂后的血清提取物与放射性碘标记的hGH-B和C一起孵育长达24小时。每隔一段时间取等分试样通过聚丙烯酰胺凝胶电泳进行分析，随后进行放射自显影和放射性条带计数。未发现转化为hGH-D和E或相互转化的证据。结论是内源性循环纤溶酶在hGH转化为其“活化”同型激素过程中不起主要作用。
