Stefin Family Gene

**Semantic type:** Gene or Genome

**Definition:** One of three inhibitory families in the cystatin superfamily (including type 2 cystatins and kininogens), Stefin Family Genes (type 1 cystatins) encode intracellular cysteine thiol protease inhibitors of papain and cathepsins B, H, and L. Cystatin Superfamily proteins contain multiple cystatin-like sequences; some are active cysteine protease inhibitors, while others have lost or perhaps never acquired this activity. (NCI)

**Synonyms:** - Cystatin 1 Family Gene