RAPID AFFINITY CHROMATOGRAPHIC METHOD FOR THE ISOLATION OF HUMAN CATHEPSIN-H

Cathepsin H was purified by a single-step affinity chromatographic met hod from crude human kidney extract. The affinity medium consisted of low-molecular-mass cysteine proteinase inhibitors from potato tubers ( PCPIs) coupled to cyanogen bromide-activated Sepharose. The yield of t he method is comparable to that of the classical methods. Isoelectric focusing and sodium dodecyl sulphate polyacrylamide electrophoresis sh owed high purity of the isolated cathepsin H. N-Terminal sequence anal ysis revealed that intact single-chain cathepsin H was obtained. Bindi ng of the enzyme to the PCPI-Sepharose showed that a free SH group in the cysteine proteinase is not required for complex formation.