Cystatin A ELISA Kits

Protease inhibitors are vital in many biological processes which rely on preventing or controlling the degradation of proteins. The cystatin family of inhibitors bind tightly but reversibly to cysteine proteases, i.e. those which have a cysteine at their active site, in order to inhibit their activity. Some of the members are active cysteine protease inhibitors. The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences. Cystatins are present in most higher organisms, from potatoes to people, where they control rates of protein turnover and combat parasitic and viral invasion. There are three inhibitory families in the superfamily, including the type 1 cystatins (stefins), type 2 cystatins, and kininogens. They form tight complexes with papain and the cathepsins B, H, and L. The protein is one of the precursor proteins of cornified cell envelope in keratinocytes and plays a role in epidermal development and maintenance. Stefins have been proposed as prognostic and diagnostic tools for cancer.

This is an intracellular thiol proteinase inhibitor. Has an important role in desmosome-mediated cell-cell adhesion in the lower levels of the epidermis. In humans, cystatins are implicated in a variety of diseases. Deficiency in Stefin B, a type 1 cystatin, is implicated in the neurological disorder myoclonus epilepsy, whilst a lack of the type 2 cystatin C leads to the thinning of arteries and ultimately aneurism. One of cystatin CÕs roles is to regulate the proteases that degrade the extracellular matrix, so without it artery walls can become thin and burst. Excess cystatin C is implicated in diseases such as atherosclerosis, diabetes, obesity, coronary heart disease, stroke, cerebral haemorrhage and dementia. The level of cystatin C in the bloodstream is used clinically as a marker of kidney function; raised levels suggest that the kidneys are not working optimally.