Purity: > 95 % by SDS - PAGE Format: : Liquid. In 20mM Tris-HCl buffer(pH 8.0) containing 10% glycerol, 1mM DTT, 0.1M NaCl.. CYB5R3 is a cytochrome b5 reductasecytochrome b5 reductase, which includes a membrane-bound form in somatic cells (anchored in the endoplasmic reticulum, mitochondrial and other membranes) and a soluble form in erythrocytes. The membrane-bound form exists mainly on the cytoplasmic side of the endoplasmic reticulum and functions in desaturation and elongation of fatty acids, in cholesterol biosynthesis, and in drug metabolism. The erythrocyte form is located in a soluble fraction of circulating erythrocytes and is involved in methemoglobin reduction. The membrane-bound form has both membrane-binding and catalytic domains, while the soluble form has only the catalytic domain. Mutations in this gene cause methemoglobinemias. Recombinant human CYB5R3 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.