L ascorbate—cytochrome b5 reductase

In enzymology, a -ascorbate—cytochrome-b₅ reductase (EC 1.10.2.1) is an enzyme that catalyzes the chemical reaction

L-ascorbate + ferricytochrome b₅ ⇌ monodehydroascorbate + ferrocytochrome b₅ + H⁺

Thus, the two substrates of this enzyme are L-ascorbate and ferricytochrome b₅, whereas its 3 products are monodehydroascorbate, ferrocytochrome b₅, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on diphenols and related substances as donor with a cytochrome as acceptor. The systematic name of this enzyme class is L-ascorbate:ferricytochrome-b₅ oxidoreductase. This enzyme is also called ascorbate-cytochrome b₅ reductase.