Cholesterol Esterase from Pseudomonas sp.

This enzyme is useful for enzymatic determination of total cholesterol when coupled with cholesterol oxidase in clinical analysis.

Cholesterol esterase (CE) is a reversible enzyme that can hydrolyze or synthesize fatty acid esters of cholesterol and other sterols. Hydrolysis of water insoluble long chain fatty acid esters requires bile salt activation. Hydrolysis of water soluble esters of short chain fatty acids and lysophospholipids does not require activation by bile salts. It also hydrolyzes tri-, di-, and mono-acylglycerols, phospholipids, lysophospholipids, and ceramide. The enzyme may have multiple functions in lipid and lipoprotein metabolism, and atherosclerosis.

Stability: Stable at –20°C for at least one year
Isoelectric point: 5.9 ± 0.1
Michaelis constants: 5.4 x 10‾⁵M (Linoleate), 6.6 x 10‾⁵M (Oleate)
3.7 x 10‾⁵M (Linolenate), 1.5 x 10‾⁴M (Palmitate)
1.2 x 10‾⁴M (Myristate), 2.3 x 10‾⁵M (Stearate)
Inhibitors: Hg^++, Ag⁺, ionic detergents
Optimum pH: 7.0 − 9.0
Optimum temp: 40°C
pH Stability: pH 5.0 − 9.0 (25°C, 24hr)
Thermal stability: Below 55°C (pH 7.5, 10min)

One unit will hydrolyze 1.0 μmole of cholesteryl oleate to cholesterol and oleic acid per min at pH 7.0 at 37 °C in the presence of taurocholate.