Human albumin synthesis via an albumin precursor in liver tissue slices

Summary A precursor of plasma albumin in man was identified in liver obtained from cadaver renal transplant donors. After 30 min incubation with¹⁴C-(U) leucine, most of the labeled immunoreactive albumin was identified as proalbumin, as was evident from its characteristic elution profile on DEAE cellulose 52. After an additional 30 min incubation with unlabeled leucine (60 min total), no precursor from could be identified and the label coeluted with serum albumin. These data strongly suggest that human albumin is initially synthesized in a precursor form and is subsequently transformed into serum albumin.This work was supported by grants from the Deutsche Forschungsgemeinschaft, the National Institutes of Health (CA 123896, AM 191241, CA 142940), and the Hochschulstiftung an der Universität Bern.We gratefully acknowledge the excellent technical assistance of Ms Kathleen O'Laughlin and Ms Edith Junker-Riesen.