CATHEPSIN D

Uses

Cathepsin D, human liver is useful for inhibitor screening, kinetic studies, and cleavage of substrates in vitro or in tissue culture. It contains the mannose-6-phosphate lysosomal localization signal that targets the enzyme to the lysosomal compartment where it functions in the normal degradation of proteins. It is a useful prognostic indicator for breast cancer.

Uses

Cathepsin D from human liver has been used:

• in β-secretase activity assay
• for enzymatic degradation of amyloid β 1-42
• in microinjection of human foreskin fibroblasts

General Description

Cathepsin D is an aspartic protease, which is located in lysosomes. It is involved in protein catabolism and maintains hormone and antigen processing. Cathepsin D is implicated in neoplasia and neurodegenerative changes. It regulates lysosomal proteolysis and endogenous fibrinolysis.

Biochem/physiol Actions

Cathepsin D is an endosomal-lysosomal aspartic protease implicated in breast cancer metastasis and Alzheimer′s disease. Lysosomal release of cathepsin D has been found to precede cytochrome c release and loss of membrane potential in apoptotic human foreskin fibroblasts. Cathepsin D levels in PC12 cells increase 12 to 24 hours after apoptosis is induced.

Purification Methods

Cathepsin D is purified on a CM column after (NH4)2SO4 fractionation and dialysis, then starch-gel electrophoresis and by ultracentrifugal analysis. Finally chromatograph on a DEAE column [Press et al. Biochem J 74 501 1960].