Search results
Results From The WOW.Com Content Network
Cytochrome b5 reductase is a prevalent topic in research and clinical tests to understand the additional functions of the enzyme in other metabolic pathways in the body. Mice and flies are common model organisms used to test for the relationship of cytochrome b5 reductase with the overall health of living organisms.
Also, vitamin C can occasionally reduce cyanosis associated with chronic methemoglobinemia, and may be helpful in settings in which methylene blue is unavailable or contraindicated (e.g., in an individual with G6PD deficiency). [22] Diaphorase (cytochrome b5 reductase) normally contributes only a small percentage of the red blood cell's ...
The structure of cytochrome b5 reductase, the enzyme that converts methemoglobin to hemoglobin. [1]Methemoglobin (British: methaemoglobin, shortened MetHb) (pronounced "met-hemoglobin") is a hemoglobin in the form of metalloprotein, in which the iron in the heme group is in the Fe 3+ state, not the Fe 2+ of normal hemoglobin.
The principal biological role of cytochrome b 5 is reduction of methemoglobin, so cytochrome b 5 deficiency can also result in elevated methemoglobin levels and/or methemoglobinemia, similarly to deficiency of cytochrome b 5 reductase (methemoglobin reductase). [1]
Additionally, the oxygen that is already bound is held more tightly to the hemoglobin due to a higher affinity, resulting in less oxygen delivery. A methemoglobin level > 1.5 g/dL causes cyanosis. The most common congenital cause is a deficiency in the enzyme cytochrome b5 reductase which reduces methemoglobin in the blood. [22]
Mutations in the CYB5R3 gene cause methemoglobinemia types I and II. This is a rare autosomal recessive disease due to a deficiency of isoform of NADH-cytochrome b5 reductase. [13] Many mutations of this gene and the subsequent disease manifestation have been described. [14] The disease manifests as the accumulation of oxidized Fe+3 in humans. [10]
EC 1.6.2.2 cytochrome-b 5 reductase. NADH + H + + 2 ferricytochrome b 5 → NAD + + 2 ferrocytochrome b 5. EC 1.10.2.1 L-ascorbate—cytochrome-b 5 reductase. L-ascorbate + ferricytochrome b 5 → monodehydroascorbate + ferrocytochrome b 5. EC 1.14.18.2 CMP-N-acetylneuraminate monooxygenase. CMP-N-acetylneuraminate + 2 ferrocytochrome b 5 + O 2 ...
Methemoglobin cannot bind oxygen, which means it cannot carry oxygen to tissues. In human blood a trace amount of methemoglobin is normally produced spontaneously; the enzyme methemoglobin reductase is responsible for converting methemoglobin back to hemoglobin .