The Liquid Stable (LS) 2-Part Enzymatic Homocysteine assay is intended for in vitro quantitative determination of total homocysteine in human serum and plasma.
In the Axis-Shield Enzymatic Homocysteine assay, bound or dimerised homocysteine (oxidised form) is reduced to free homocysteine, which then reacts with serine catalysed by cystathionine beta-synthase (CBS) to form L-cystathionine. Cystathionine in turn is broken down by cystathionine beta-lyase (CBL) to form homocysteine, pyruvate and ammonia. Pyruvate is then converted by lactate dehydrogenase (LDH) to lactate with NADH as coenzyme. The rate of NADH conversion to NAD is directly proportional to the concentration of homocysteine.