PubMed Health⌕ Search

Biomedical subjects

E Hodgson

Publications and source records attributed to E Hodgson.

22 records · Page 2Linked to original sources
PubMed1975

The occurrence of multiple forms of cytochrome P-450 in hepatic microsomes from untreated rats and mice.

The hepatic microsomes of rat and mice were subfractionated by the procedure of Dallner. When a 1.3 M sucrose lower layer was used for the two-step discontinuous gradient, no differences in spectral characteristics were noted between subfractions, though the smooth fractions (SER) had higher oxidative activity towards the substrates tested. When lower layers of 1.05, 1.1 or 1.15 M sucrose were used, and the SER isolated contained cytochdrome P-450 with significantly different spectral characteristics from that of the rough fraction (RER). The SER cytochrome P-450 had a wavelength maximum in the carbon-monoxide reduced difference spectrum that was significantly lower (ca. 1.0 nm) than that in the RER. In addition, the type I:CO-reduced spectral ratio of these fractions is significantly elevated. These data indicate that liver microsomes from untreated rats and mice contain more than one cytochrome P-450 and that of these cytochromes may be located in different parts of the endoplasmic reticulum.

Animals↗
PubMedDate not supplied

The role of the flavin-containing monooxygenase (EC 1.14.13.8) in the metabolism and mode of action of agricultural chemicals.

1. The flavin-containing monooxygenase (FMO) (EC 1.14.13.8) is a versatile enzyme that catalyses the monooxygenation of a large number of xenobiotic soft nucleophiles ranging from inorganic ions to organic compounds with nitrogen, sulphur, phosphorus or selenium heteroatoms. 2. The substrate specificity relative to agricultural chemicals is discussed and compared with that of the cytochrome P-450-dependent monooxygenase system. The relative activity of these two enzymes towards common substrates varies from substrate to substrate and from tissue to tissue as is shown in the case of the insecticide, phorate and the hepatotoxicant, thiobenzamide. 3. The products of FMO action may be chemically different (e.g. nicotine) to those from P-450, or the two enzymes may produce different isomers of the same product (e.g. phorate). 4. Recent studies have demonstrated that, in the rabbit, the FMOs from liver and lung are different gene products which differ not only in primary sequence but also in physical, catalytic and immunochemical properties. These studies are being extended to include other tissues such as skin and brain. 5. Immunocytochemical localization of FMO in lung and skin correlates well with measurements of the oxidation of methimazole, a specific FMO substrate.

Agrochemicals↗