Interaction of human cathepsin C with chicken cystatin.
Cathepsin C was purified from human spleen by a rapid procedure, which included homogenization, ammonium sulfate precipitation, gel filtration on Sephacryl S-200 and finally affinity chromatography on chicken cystatin-Sepharose. The interaction between cathepsin C and chicken cystatin was further characterized. It was found to be accompanied by a maximum decrease in fluorescence emission intensity at 336 nm. Fluorescence titration showed that human cathepsin C can bind four chicken cystatin molecules. The 4:1 binding stoichiometry was confirmed by titration monitored by the loss of enzyme activity. A non-competitive-competitive type of inhibition was determined from a double-reciprocal Lineweaver-Burk plot with a Ki value of 0.22 nM for the non-competitive inhibition.
Dolenc
I
I
Department of Biochemistry and Molecular Biology, J. Stefan Institute, Ljubljana, Slovenia.
Turk
B
B
Kos
J
J
Turk
V
V
D000818:Animals; D020789:Cathepsin C; D002645:Chickens; D002846:Chromatography, Affinity / Q000379:methods*; D015891:Cystatins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism*; D006801:Humans; D013050:Spectrometry, Fluorescence; D017186:Titrimetry
D015891:Cystatins; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D020789:Cathepsin C