Autocatalytic processing of recombinant human procathepsin B is a bimolecular process.
Cathepsin B and other lysosomal cysteine proteinases are synthesized as inactive zymogens, which are converted to their mature forms by other proteases or by autocatalytic processing. Procathepsin B autoactivation was shown in vitro at pH 4.5 to be a bimolecular process with K(s) and k(cat) values of 2.1+/-0.9 microM and 0.12+/-0.02 s(-1)6.0. However, in the presence of 0.5 microg/ml of dextran sulfate, relatively rapid processing is observed even at pH 6.5 (t(1/2) approximately 90 min), suggesting that glycosaminoglycans are involved in in vivo processing of lysosomal cysteine proteases.
Rozman
J
J
Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia. jerca.rozman@ijs.si
Stojan
J
J
Kuhelj
R
R
Turk
V
V
Turk
B
B
D002384:Catalysis / Q000187:drug effects; D002401:Cathepsin B / Q000737:chemistry / Q000378:metabolism*; D002942:Circular Dichroism; D016264:Dextran Sulfate / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004792:Enzyme Precursors / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
D004792:Enzyme Precursors; D011994:Recombinant Proteins; D016264:Dextran Sulfate; C057832:procathepsin B; D002401:Cathepsin B