The protein encoded by this gene is a growth-related cell surface protein. It was identifed because it reacts with the monoclonal antibody KI in cells, such as the ovarian carcinoma line OVCAR-3, also expressing the CAKI surface glycoprotein. The encoded protein has two enzymatic activities: catalysis of hydroquinone or NADH oxidation, and protein disulfide interchange. The two activities alternate with a period length of about 24 minutes. The encoded protein also displays prion-like properties. Two transcript variants encoding different isoforms have been found for this gene.