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Cytochrome-B(5) Reductase MeSH Descriptor Data 2025
A FLAVOPROTEIN oxidoreductase that occurs both as a soluble enzyme and a membrane-bound enzyme due to ALTERNATIVE SPLICING of a single mRNA. The soluble form is present mainly in ERYTHROCYTES and is involved in the reduction of METHEMOGLOBIN. The membrane-bound form of the enzyme is found primarily in the ENDOPLASMIC RETICULUM and outer mitochondrial membrane, where it participates in the desaturation of FATTY ACIDS; CHOLESTEROL biosynthesis and drug metabolism. A deficiency in the enzyme can result in METHEMOGLOBINEMIA.
Entry Term(s)
Methemoglobin Reductase
NADH Cytochrome B5 Reductase
NADH Methemoglobin Reductase
NADH-Cytochrome B5 Reductase
NADH-Ferrihemoglobin Reductase
Registry Numbers
EC 1.6.2.2
EC 1.6.2.2
Related Numbers
9032-25-1
EC 1.6.2.2
Previous Indexing
Cytochrome Reductases (1975-2003)
NADH, NADPH Oxidoreductases (1975-1990)
Oxidoreductases (1973-1974)
Public MeSH Note
2004; CYTOCHROME B(5)REDUCTASE was indexed under CYTOCHROME REDUCTASES 1975-2003 & under OXIDOREDUCTASES 1973-1974; for METHEMOGLOBIN REDUCTASE see METHEMOGLOBIN REDUCTASE 1991-2003, see NADH, NADPH OXIDOREDUCTASES 1975-1990
History Note
2004; use CYTOCHROME B(5) REDUCTASE (NM) 1980-2003
A FLAVOPROTEIN oxidoreductase that occurs both as a soluble enzyme and a membrane-bound enzyme due to ALTERNATIVE SPLICING of a single mRNA. The soluble form is present mainly in ERYTHROCYTES and is involved in the reduction of METHEMOGLOBIN. The membrane-bound form of the enzyme is found primarily in the ENDOPLASMIC RETICULUM and outer mitochondrial membrane, where it participates in the desaturation of FATTY ACIDS; CHOLESTEROL biosynthesis and drug metabolism. A deficiency in the enzyme can result in METHEMOGLOBINEMIA.
The soluble, erythrocyte form of cytochrome-B(5) reductase. It catalyzes the reduction of methemoglobin (ferrihemoglobin) to hemoglobin (ferrohemoglobin).