Proteolytically active complexes of cathepsin L and a cysteine proteinase inhibitor; purification and demonstration of their formation in vitro.
Proteolytically active complexes of the proteinase cathepsin L, with an endogenous inhibitor of cysteine proteinases, were purified from sheep liver. The complexes were active against the synthetic substrate Z-Phe-Arg-NHMec and also the proteins azocasein and gelatin. The composition of the complexes was demonstrated by Western blotting, after reducing and nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis with monospecific antibodies raised against purified sheep liver cathepsin L and purified sheep liver cysteine proteinase inhibitor (probably stefin B). Similar complexes could be formed in vitro, by coincubation of purified sheep liver cathepsin L with the purified sheep liver cystatin at a pH of 5.5 or higher.
Pike
R N
RN
Department of Biochemistry, University of Natal, Pietermaritzburg, South Africa.
Coetzer
T H
TH
Dennison
C
C
D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D056668:Cathepsin L; D002403:Cathepsins / Q000302:isolation & purification / Q000378:metabolism*; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D015891:Cystatins / Q000302:isolation & purification / Q000378:metabolism*; D003546:Cysteine Endopeptidases; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D046911:Macromolecular Substances; D008954:Models, Biological; D008970:Molecular Weight; D011485:Protein Binding; D012756:Sheep; D013379:Substrate Specificity
D015891:Cystatins; D046911:Macromolecular Substances; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D056668:Cathepsin L