enzymology Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

, an isobutyryl-CoA mutase () is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

that catalyzes the

chemical reaction A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...

:2-methylpropanoyl-CoA

\rightleftharpoons

butanoyl-CoA Hence, this enzyme has one substrate, 2-methylpropanoyl-CoA, and one

product Product may refer to: Business * Product (business), an item that serves as a solution to a specific consumer problem. * Product (project management), a deliverable or set of deliverables that contribute to a business solution Mathematics * Produ ...

, butanoyl-CoA. This enzyme belongs to the family of

isomerase Isomerases are a general class of enzymes that convert a molecule from one isomer to another. Isomerases facilitate intramolecular rearrangements in which bonds are broken and formed. The general form of such a reaction is as follows: A–B � ...

s, specifically those intramolecular

transferase A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of di ...

s transferring other groups. The

systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ...

of this enzyme class is 2-methylpropanoyl-CoA CoA-carbonylmutase. Other names in common use include isobutyryl coenzyme A mutase, and butyryl-CoA:isobutyryl-CoA mutase. It uses

adenosylcobalamin Adenosylcobalamin (AdoCbl), also known as coenzyme B12, cobamamide, and dibencozide, is, along with methylcobalamin (MeCbl), one of the biologically active forms of vitamin B12. Adenosylcobalamin participates as a cofactor in radical-mediated 1,2 ...

as a cofactor, which is bound at the enzyme's

vitamin B12-binding domain In molecular biology, the vitamin B12-binding domain is a protein domain which binds to cobalamin (vitamin B12). It can bind two different forms of the cobalamin cofactor, with cobalt bonded either to a methyl group (methylcobalamin) or to 5'-d ...

. The

mechanism of action In pharmacology, the term mechanism of action (MOA) refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect. A mechanism of action usually includes mention of the specific molecular targe ...

of the enzyme is to generate a 5′-

deoxyadenosyl radical A deoxyadenosyl radical is a free radical that is structurally related to adenosine by removal of a 5′-hydroxy group from adenosine. This radical occurs in nature as a reactive intermediate. It is generated by radical SAM Radical SAM is a desig ...

by homolytic cleavage of the cobalt-carbon bond of the cofactor. This radical abstracts a hydrogen atom from the substrate to initiate the rearrangement reaction.

References

* * EC 5.4.99 Cobalt enzymes Enzymes of unknown structure {{isomerase-stub