Cholesterol Esterase

Cholesterol esterase catalyzes the following reaction:

The enzyme is found primarily in pancreas and pancreatic juice, but in other tissues as well. Bile salts, such as cholate and its conjugates, are required to stabilize the enzyme in its native polymeric form and to protect it from proteolytic hydrolysis in the intestine (Vahouny and Treadwell 1968). Cholesterol esterase finds clinical applications in the determination of serum cholesterol (Allain et al. 1974).

Characteristics of Cholesterol Esterase from Porcine Pancreas:

Enzymatic Reaction (image will open in a new window)

Molecular weight: 400,000 (Hyun et al. 1971).

Composition: A hexamer of 65,000 - 69,000 molecular weight subunits. Bile salts are required for hexamer stabilization (Hyun et al. 1971).

Optimum pH: For esterification, 6.1 - 6.2; for hydrolysis, 6.6 - 7.0 (Vahouny and Treadwell 1968).

Activators: Cholate, glycocholate, taurocholate (Vahouny et al. 1964).

Inhibitors: PMSF and p-chloromercuribenzoate (Hyun et al. 1971; Vahouny et al. 1964).