Glomerular basement membrane collagen and activities of the intracellular enzymes of collagen biosynthesis in congenital nephrotic syndrome of the Finnish type

Abstract

The composition of pepsin-solubilized glomerular basement membrane (GBM) collagen was studied in kidneys from patients with congenital nephrotic syndrome of the Finnish type (CNF). The 3-hydroxyproline content in the GBM collagen in CNF was only about one half of that noted in the controls. The alanine content was slightly higher in CNF, but no differences were found in the contents of the other amino acids or carbohydrates. Analysis of the GBM collagen by sodium dodecyl sulphate polyacrylamide gel electrophoresis after reduction indicated a lower proportion of one of the major polypeptide chains in CNF than in the controls, while a higher proportion of one low molecular weight minor component was noted. The activities of the five intracellular enzymes of collagen biosynthesis, including prolyl 3-hydroxylase, were not significancy altered in the CNF kidney cortex samples when compared with the controls.