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Enzyme Kinetics Studies on 29‐kDa Human Liver C athepsin L
Author(s) -
Pietra Daniele,
Borghini Alice,
Ricci Claudio,
Bianucci Anna M.
Publication year - 2014
Publication title -
chemical biology and drug design
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.59
H-Index - 77
eISSN - 1747-0285
pISSN - 1747-0277
DOI - 10.1111/cbdd.12357
Subject(s) - chemistry , enzyme , enzyme kinetics , kinetics , extracellular , biochemistry , cathepsin l , cathepsin d , cystatin , cathepsin , cystatin c , active site , physics , quantum mechanics , renal function
Enzyme kinetics studies reported in the literature showed that human liver Cathepsin L is active only at lysosomal acidic pH values, while biochemical studies in living cells showed that the enzyme works even at neutral pH values (in a condition compatible with the extracellular compartment). Such an apparent ambiguity highlighted the need of analysing in depth the kinetics of ~29‐kDa Cathepsin L , which is the form commonly used in experiments. The stability and catalytic activity of this enzyme were investigated at different pH values, reducing and non‐reducing environments, presence of copper, iron and zinc ions, and presence of the natural modulator/inhibitor cystatin B . Our experiments showed that ~29‐kDa human liver Cathepsin L is stable and catalytically functional even at neutral pH values and under non‐reducing conditions, which simulate the extracellular compartment. Under these conditions, Cathepsin L was also proved to interact with cystatin B , being also modulated by physiological concentrations of Cu ++ , Fe ++ and Zn ++ . This paper suppose an advance in the comprehension of the catalytic properties of human liver Cathepsin L , its implications in different physiological processes and its potential use within a drug screening programme in which agents acting extracellularly are being considered.