Plasmin: its role in the extracellular processing of progalanin in tumor tissue.

Galanin is a neuropeptide that is widely distributed in the central and peripheral nervous systems. In a previous study, we showed that a small cell lung carcinoma (SCLC) cell line, SBC-3A, released progalanin but not galanin, and that progalanin was then converted to galanin(1-20), the active form. Because the galanin(1-20) had undergone hydrolysis at Arg and Lys residues, the protease concerned was surmised to have a trypsin-like activity.