title: Reconstitution of a purified and partially active low Km iodothyronine 5'-deiodinase with phospholipids.
abstract: We previously reported the detergent-extraction and purification to homogeneity from rat liver microsomes of an iodothyronine 5'-deiodinase which differed from the type I enzyme in its molecular size as well as its Km, thiol responsiveness, and its expected sensitivity to the antithyroid drug, propylthiouracil. The specific activity enhancement (22-fold) of the delipidated enzyme was, however, relatively modest. We report here that the purified enzyme can be activated a further 25-fold by reconstitution in microsomal phospholipids and, to a lesser extent, in soybean phospholipids. The data suggest that a native lipid environment is necessary for proper conformation of the enzyme for optimal activity.
authors.affiliation: Department of Medicine, Boston University School of Medicine, Massachusetts 02118.
authors.forename: A
authors.initials: A
authors.lastname: Goswami
authors.forename: I N
authors.initials: IN
authors.lastname: Rosenberg
mesh_terms: D000818:Animals; D004789:Enzyme Activation; D007453:Iodide Peroxidase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008862:Microsomes, Liver / Q000201:enzymology*; D010743:Phospholipids / Q000737:chemistry*; D051381:Rats; D013025:Glycine max
chemical_list: D010743:Phospholipids; D007453:Iodide Peroxidase