Enzyme Kinetics Studies on 29‐kDa Human Liver Cathepsin L. (21st June 2014)

• Record Type: Journal Article
• Authors: Pietra, Daniele; Borghini, Alice; Ricci, Claudio; Bianucci, Anna M.
• Is Part Of: Chemical biology & drug design. Volume 84:Number 6(2014:Dec.)
• Page Start: 648
• Page End: 658
• Publication Date: 2014-06-21
• Subjects: Drugs -- Design -- Periodicals; Pharmaceutical chemistry -- Periodicals; Biochemistry -- Periodicals; 615.19005
• DOI: 10.1111/cbdd.12357
• Languages: English
• ISSNs: 1747-0277

Abstract

<abstract abstract-type="main" id="cbdd12357-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>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.</p> </abstract>