What is the difference between isomerase and epimerase with examples?

Answer 1

In biochemistry, an isomerase is an enzyme that catalyzes the structural rearrangement of isomers.

F6P can be converted to

glucose-6-phosphate (G6P) by phosphoglucoisomerase.

There are two main forms of isomerism: structural isomerism and stereoisomerism (spatial isomerism).

structural isomers, sometimes referred to as constitutional isomers, the atoms and functional groups are joined together in different ways. Structural isomers may or may not belong to the same functional group.[

For example, two position isomers would be 2-fluoropropane and 1-fluoropropane, illustrated on the left side of the diagram above.

In stereoisomers the bond structure is the same, but the geometrical positioning of atoms and functional groups in space differs.

Epimerases and racemases are isomerase enzymes that catalyze the inversion of stereochemistry in biological molecules.

Human epimerases include methylmalonyl-CoA epimerase, involved in the metabolic breakdown of the amino acids isoleucine, methionine and valine, and UDP-glucose 4-epimerase, which is used in the final step of galactose metabolism - catalyzing the reversible conversion of UDP-galactose to UDP-glucose.

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Answer 2

Isomerases are enzymes that catalyze the interconversion of isomers, whereas epimerases specifically catalyze the conversion of epimers, which are a subtype of isomers with different configurations at one specific chiral center. An example of an isomerase is aldose-ketose isomerase, which converts aldose sugars to ketose sugars. An example of an epimerase is galactose epimerase, which catalyzes the conversion of glucose to galactose or vice versa by changing the configuration at the C-4 carbon atom.