Cathepsin D Activity Assay Kit (Fluorometric)

Supplementary info

This supplementary information is collated from multiple sources and compiled automatically.

Activity summary

Cathepsin D also known as CTSD is a protein with a mass of approximately 45 kDa. It functions as an aspartyl protease and is expressed in lysosomes across various tissues including the liver and kidneys. This enzyme acts by cleaving peptide bonds within proteins which is essential for protein degradation and turnover. Cathepsin D exists as precursor forms that become activated in the acidic environment of the lysosome. It plays a critical role in normal cellular processes by maintaining protein homeostasis.

Biological function summary

The enzymatic activity of Cathepsin D is important for cellular maintenance and apoptosis. This protease does not act within larger protein complexes but contributes to the degradation of extracellular and intracellular proteins. It mediates processes like antigen processing where it deconstructs proteins into peptides that are presented on major histocompatibility complex (MHC) molecules. ELISA tests can quantify its expression levels sometimes termed as CTSD activity in various biological samples offering insights into its role within cellular environments.

Pathways

Cathepsin D involvement includes the lysosomal degradation pathway and the apoptotic signaling pathway. In the lysosomal degradation pathway Cathepsin D breaks down proteins and peptides a process important for cellular recycling and energy release. It interacts with other lysosomal enzymes such as Cathepsin B in this pathway ensuring comprehensive breakdown of cellular waste. The apoptotic signaling pathway involves the regulation of programmed cell death where Cathepsin D can influence the activation of downstream proteins like Bcl-2 and Bax which control cell survival.

Associated diseases and disorders

The overexpression of Cathepsin D links to breast cancer and Alzheimer's disease. In breast cancer increased Cathepsin D expression correlates with tumor progression and metastasis influencing tumor behavior through interactions with other proteins involved in cell proliferation. Alzheimer's disease features the involvement of Cathepsin D in the breakdown of amyloid precursor protein which relates to amyloid beta plaque accumulation. The abnormal activity of Cathepsin D in these disorders makes it a potential target for therapeutic antibodies such as CTSD antibodies which aim to regulate its function.