Purification, characterization and reconstitution of CMP-N-acetylneuraminate hydroxylase from mouse liver

CMP-N-acetylneuraminate hydroxylase was isolated from mouse liver high speed supernatant with a yield of 0.4% and an apparent 1000-fold purification. The enzyme is a monomeric protein with a molecular weight of 66 kDa, as determined by gel filtration and SDS-PAGE. The hydroxylase system was reconstituted with Triton X-100-solubilized mouse liver microsomes and purified soluble or microsomal forms of cytochrome b5 reductase and cytochrome b5. The systems were characterized in detail and kinetic parameters for each system were determined.