[Spectrofluorimetric procedures for estimation of lysosomal cathepsins A, B C and D activities]

Unified modifications of procedures are described for estimation of lysosomal cathepsins A, B, C and D activities. The procedures are based on spectrofluorimetric determination of beta-naphthylamine in the experiments with cathepsins B and C or on spectrofluorimetric determination of fluorescamine conjugates with epsilon-NH2-groups of free amino acids in the case of cathepsins A and D. Kinetics of all the reactions studied obeyed the Michaelis-Menten equation; the enzymatic activities could be estimated at protein concentration up to 0.1 mg/ml of the experimental sample.