KetoReductase (KRED), also known as carbonyl reductase, is an enzyme that catalyzes the reversible REDOX reaction between aldehydes/ketones and alcohols, requiring coenzymes such as NAD(H) or NADP(H) as hydrogen transmitters。It has an (α/β) 8-barrel structure and the active site Asp-Tyr-Lys-His, most of which is expressed in soluble form, and widely exists in different animals, plants, yeasts and bacteria in nature。

There are three main types of keto reductases，They are Short-chain Dehydrogenase/Reductases, respectively, SDRs), Medium chain dehydrogenase/reductase (Medium - chain Dehydrogenases/Reductases, MDRs and Aldo-KetoReductases, AKRs)。The catalytic functions of the three are similar, but there are great differences in structure and properties。

The use of keto reductase for biological transformation has the advantages of strong substrate specificity, strong chiral selectivity, high conversion efficiency, not easy to generate by-products, mild reaction conditions, and little environmental pollution。With the rapid development of biotechnology, more and more KRED recombinases with excellent properties have been discovered and applied to the research of chiral alcohols as pharmaceutical and chemical intermediates。

The reaction types catalyzed by keto reductase are as follows, which can be divided into glucose system and isopropyl alcohol system according to the different ways of coenzyme regeneration。

In industry, atorvastatin, Russo vastatin, ibutinib, Monorast sodium, duloxetine, L-carnitine, ticagrelor, crizotinib, aprepitan, nepiprool and many other raw materials and intermediates have been prepared by keto reductase method。Keto reductase is the most widely used enzyme in pharmaceutical and chemical industry。