Biosyntheses and processing of lysosomal cysteine proteinases in rat macrophages.
The intracellular processing and release of three lysosomal cysteine proteinases, cathepsin B, H and L, by rat peritoneal macrophages were investigated by pulse-chase experiments. Newly synthesized procathepsins B (39 kDa), H(41 kDa) and L (39 kDa) after 15 min labeling were processed to the mature, single-chain enzymes within 1 h. The single-chain forms of cathepsin B, H and L were further processed to two-chain forms at different rates: conversion of cathepsin L to the two-chain form was rapid, whereas the conversions cathepsin B and H took at least 6 h. Macrophages released 30% of the procathepsins B and L, and 10% of the procathepsin H.
Kominami
E
E
Division of Enzyme Chemistry, Institute for Enzyme Research, University of Tokushima, Japan.
Tsukahara
T
T
Hara
K
K
Katunuma
N
N
D000818:Animals; D002250:Carbon Radioisotopes; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D008247:Lysosomes / Q000201:enzymology*; D008264:Macrophages / Q000201:enzymology*; D008715:Methionine / Q000378:metabolism; D008970:Molecular Weight; D011499:Protein Processing, Post-Translational; D051381:Rats; D011919:Rats, Inbred Strains; D013462:Sulfur Radioisotopes
D002250:Carbon Radioisotopes; D013462:Sulfur Radioisotopes; D008715:Methionine; D003546:Cysteine Endopeptidases