Cholesterol Oxidase and Its Applications

Abstract

Cholesterol oxidase (COX), a bi-functional FAD-containing microbial enzyme belongs to the family oxidoreductases. COX catalyses the oxidation of cholesterol into 4-cholesten-3-one. In recent time, cholesterol oxidase has received great attention due to its wider use in clinical (determination of serum cholesterol) laboratories practice and in the biocatalysis for the production of a number of steroids. COX has been shown to possess potent insecticidal activity, besides its use to track cell cholesterol. Moreover, COX is also implicated in the manifestation of some of the diseases of bacterial (tuberculosis), viral (HIV) and non-viral prion origin (Alzheimer's). These applications and disease mechanisms have promoted the need of screening, isolation and characterization of newer microbes from diverse habitats as a source of COX to learn more about its structural and functional aspects. In this review, we discuss microbial sources of COX, its structure and important biochemical properties besides its broad range of biological functions and applications.

Purification, characterization and amino acid content of cholesterol oxidase produced by Streptomyces aegyptia NEAE 102

“…While Yazdi and Zahraei [25] reported optimum temperature at around 50 °C and plateau between 40 and 60 °C for the purified enzyme from Streptomyces violascens . Whereas, other authors reported that the optimum temperature for cholesterol oxidase from Bacillus sp., Arthrobacter simplex and Streptomyces violascens was found to range between 50 and 60 °C and obvious enzyme thermostability [31]. The optimum temperature for cholesterol oxidase was found to be 50 °C and it retained more than 70% activity at 50 °C after 60 min of heat treatment [32].…”

Assessment of alkaline cholesterol oxidase purified from Rhodococcus sp. PKPD-CL for its halo tolerance, detergent and organic solvent stability

“…This strain was identified as the new isolate from genus Rhodococcus and denoted as Rhodococcus sp. PKPD-CL which can be considered a more significant and useful source than the earlier reported cholesterol oxidase producer Rhodococci [7]. The comparative enzyme activities could be understood by taking a glance at the Table 7.…”

“…It is also responsible for virulence of certain pathogenic species such as Mycobacterium sp. [7] and Rhodococcus equi [8]. Variety of bacterial genera such as Arthrobacter [9], Brevibacterium [10], Corynebacterium [11], Mycobacterium [12], Nocardia [13], Pseudomonas [14], Rhodococcus [15], Schizophyllum [16], Streptomyces [17], Streptoverticillium [18] etc.…”

Production of 4-Ene-3-ketosteroids in Corynebacterium glutamicum

“…The 3-OH oxidation of ∆5-3-hydroxysteroids coupled to ∆5-∆4 isomerization, a key step in the transformation of sterols into many steroids of biological relevance (e.g., progesterone, testosterone, cortisol, aldosterone, and corticosterone), has been widely used for the quantification of cholesterol in clinical and food specimens [18,19], but there are only a few examples concerning its utilization in biocatalysis [20][21][22][23]. All these biocatalytic procedures have been carried out using ChOx from different sources, but none of them have been carried out with 3β-HSD enzymes.…”