Activation of renin in an anaplastic pulmonary adenocarcinoma.
1. Biochemical characteristics of a renin-like enzyme secreted by a pulmonary adenocarcinoma have been studied. A very high renin content was revealed by both enzymatic (10.4 Goldblatt units/g of tissue) and direct radioimmunoassay of immunoreactive renin (23 Goldblatt units/g of tissue). 2. The higher value by direct radioimmunoassay suggested the presence of an inactive form of the enzyme. Indeed 40--100% activation occurred with treatment by trypsin or pepsin or prolonged dialysis at pH 7.4 with or without prior acid dialysis. This neutral activation was completely abolished by a serine proteinase inhibitor. 3. A large fraction of the renin in this tumour is inactive. In comparison with other prohormones produced in tumours the findings support strongly the proposition that renin passes through a proenzyme step in synthesis.
D000230:Adenocarcinoma / Q000201:enzymology*; D004792:Enzyme Precursors / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000201:enzymology*; D011863:Radioimmunoassay; D012083:Renin / Q000378:metabolism*
D004792:Enzyme Precursors; D012083:Renin