In enzymology, a testosterone 17beta-dehydrogenase is an

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

that

catalyzes Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycl ...

the

chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and break ...

between

testosterone Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteris ...

and androst-4-ene-3,17-dione. This enzyme belongs to the family of

oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually ...

s, specifically those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor.

Names

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 17beta-hydroxysteroid:NAD⁺ 17-oxidoreductase. Other names in common use include 17-ketoreductase and 17beta-HSD. This enzyme participates in androgen and

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal a ...

metabolism.

Variants

There are two variants of the enzyme, one that uses NAD⁺ as a substrate, and one that uses NADP⁺ as acceptor.

NAD⁺

This variant of testosterone 17beta-dehydrogenase () catalyzes the reaction :testosterone + NAD⁺

\rightleftharpoons

androst-4-ene-3,17-dione + NADH + H⁺ Thus, the two substrates of this enzyme are

and NAD⁺, whereas its 3

products 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 ...

are androst-4-ene-3,17-dione,

NADH Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an aden ...

, and H⁺.

NADP⁺

This variant of testosterone 17beta-dehydrogenase () catalyzes the reaction :testosterone + NADP⁺

\rightleftharpoons

androst-4-ene-3,17-dione + NADPH + H⁺ Thus, the two substrates of this enzyme are testosterone and NADP⁺, whereas its 3

are androst-4-ene-3,17-dione,

NADPH Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require NADP ...

, and H⁺.

References

* * *

External links

Testosterone Enhancement
EC 1.1.1 Testosterone NADH-dependent enzymes NADPH-dependent enzymes Enzymes of unknown structure Enzymes of known structure {{1.1.1-enzyme-stub

Names

Variants

NAD+

NADP+

See also

References

External links

NAD⁺

NADP⁺