Cysteine Content Assay kit

Protein contains three sulfur-containing amino acids: methionine, cystine and Cys. Among them, Cys is the only sulfur-containing amino acid containing a sulfhydryl group, which is converted from methionine and can be mutually converted with cystine. Cys participates in the formation of protein disulfide bonds and is often a component of the active center of proteins. It can also provide sulfhydryl groups for other physiological and biochemical reactions. In addition, Cys accumulates in large amounts on the skin and mucosal surface, maintains the activity of important sulfhydryl enzymes in keratinogenesis, and supplements sulfhydryl groups to maintain normal skin metabolism and regulate the underlying melanin produced by pigment cells in the lowermost layer of the epidermis. It has the functions of whitening, detoxification, improving inflammation and allergic skin.

Cys reduces phosphotungstic acid to generate tungsten blue, with an absorption peak at 600nm; calculate the Cys content by 600nm absorbance.