scholarly journals The Influence of Quinolines on Coumarin 7-Hydroxylation in Bovine Liver Microsomes and Human CYP2A6

2002 ◽  
Vol 48 (2) ◽  
pp. 118-125 ◽  
Author(s):  
Yoshie Hirano ◽  
Mayumi Uehara ◽  
Ken-ichi Saeki ◽  
Taka-aki Kato ◽  
Kazuhiko Takahashi ◽  
...  
Keyword(s):  
Liver Microsomes ◽  
Bovine Liver ◽  
Coumarin 7

Purification and Properties of 4-Hydroxybiphenyl UDP-Glucuronyltransferase from Bovine Liver Microsomes

1992 ◽  
Vol 112 (5) ◽  
pp. 578-582 ◽  
Author(s):  
Hiroyuki Kanehara ◽  
Hiroghi Yokota ◽  
Masahiko Sato ◽  
Akira Yuasa
Keyword(s):  
Liver Microsomes ◽  
Bovine Liver ◽  
Purification And Properties

Inhibition of Coumarin 7-Hydroxylase Activity in Human Liver Microsomes

1997 ◽  
Vol 341 (1) ◽  
pp. 47-61 ◽  
Author(s):  
Alison J. Draper ◽  
Ajay Madan ◽  
Andrew Parkinson
Keyword(s):  
Human Liver ◽  
Liver Microsomes ◽  
Human Liver Microsomes ◽  
Hydroxylase Activity ◽  
Coumarin 7

scholarly journals Isomerization of all-trans-retinoic acid to 9-cis-retinoic acid

1994 ◽  
Vol 299 (2) ◽  
pp. 459-465 ◽  
Author(s):  
J Urbach ◽  
R R Rando
Keyword(s):  
Biological Activity ◽  
Retinoic Acid ◽  
Liver Microsomes ◽  
Equilibrium Concentration ◽  
Bovine Liver ◽  
Thiol Groups ◽  
First Order ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Liver Membranes

The discovery of the biological activity of 9-cis-retinoic acid raises questions as to its mode of biosynthesis. A simple mechanism involves the direct isomerization of all-trans-retinoic acid to 9-cis-retinoic acid. It is shown here that bovine liver membranes, but not supernatant fractions, can isomerize all-trans-retinoic acid into 9-cis-retinoic acid and 13-cis-retinoic acid. The concentration of 9-cis-retinoic acid generated approaches its equilibrium concentration, which is determined here to be approximately 15%. However, the isomerization process could not be shown to be saturable, and is first-order in all-trans-retinoic acid in the concentration range measured (8.3 nM to 3 microM). Isomerization reactions measured using bovine liver microsomes appear to be mediated by thiol groups, as they can be blocked by group-specific thiol-blocking reagents such as N-ethylmaleimide. It is interesting to note that the non-stereospecific behaviour observed here mimics what is observed when all-trans-retinoic acid is applied to cells. Finally, significant formation of 9-cis-retinoids was not found when the reaction was carried out with liver microsomes and either all-trans-retinol or all-trans-retinal.

Inhibition of cytochrome P450 2A participating in coumarin 7-hydroxylation in pig liver microsomes

2011 ◽  
Vol 34 (5) ◽  
pp. 424-429
Author(s):  
Z.-Y. LIU ◽  
M.-H. DAI ◽  
Y.-F. TAO ◽  
D.-M. CHEN ◽  
Z.-H. YUAN
Keyword(s):  
Cytochrome P450 ◽  
Liver Microsomes ◽  
Pig Liver ◽  
Coumarin 7

scholarly journals Stimulation of the dithiol-dependent reductases in the vitamin K cycle by the thioredoxin system. Strong synergistic effects with protein disulphide-isomerase

1992 ◽  
Vol 281 (1) ◽  
pp. 255-259 ◽  
Author(s):  
B A M Soute ◽  
M M C L Groenen-van Dooren ◽  
A Holmgren ◽  
J Lundström ◽  
C Vermeer
Keyword(s):  
Vitamin K ◽  
Synergistic Effects ◽  
Liver Microsomes ◽  
Bovine Liver ◽  
Secretory Cells ◽  
Protein Disulphide Isomerase ◽  
Vitamin K Cycle ◽  
Thioredoxin System

It has been shown previously that the thioredoxin system (thioredoxin + thioredoxin reductase + NADPH) may replace dithiothreitol (DTT) as a cofactor for vitamin KO and K reductase in salt-washed detergent-solubilized bovine liver microsomes. Here we demonstrate that the system can be improved further by adding protein disulphide-isomerase (PDI) to the components mentioned above. Moreover, NADPH may be replaced by reduced RNAase as a hydrogen donor. In our in vitro system the various protein cofactors were required at concentrations 2-5 orders of magnitude lower than that of DDT, whereas the maximal reaction rate was about 3-fold higher. PDI stimulated the thioredoxin-driven reaction about 10-fold, with an apparent Km value of 8 microM. These data suggest that in the vitro system the formation of disulphide bonds is somehow linked to the vitamin K-dependent carboxylation of glutamate residues. In vivo, both disulphide formation and vitamin K-dependent carboxylation are post-translational modifications taking place at the luminal side of the endoplasmic reticulum of mammalian secretory cells. The possibility that the reactions are also coupled in vivo is discussed.

scholarly journals Identification of the human liver cytochrome P-450 responsible for coumarin 7-hydroxylase activity

1990 ◽  
Vol 267 (2) ◽  
pp. 365-371 ◽  
Author(s):  
J S Miles ◽  
A W McLaren ◽  
L M Forrester ◽  
M J Glancey ◽  
M A Lang ◽  
...  
Keyword(s):  
Human Liver ◽  
Liver Microsomes ◽  
Microsomal Protein ◽  
Hydroxylase Activity ◽  
Liver Cytochrome ◽  
Partial Length ◽  
Coumarin 7 ◽  
Human Livers ◽  
Cell Expression ◽  
Cytochrome P 450

1. We have constructed a full-length human liver cytochrome P450IIA cDNA from a partial-length clone by oligonucleotide-directed mutagenesis, and subcloned it into the monkey kidney (COS-7) cell expression vector, pSVL. 2. The cDNA encodes a 49 kDa protein with coumarin 7-hydroxylase (COH) activity which cross-reacts with antisera to the mouse cytochrome P-450 isoenzyme responsible for COH activity and comigrates with a human liver microsomal protein. 3. Western blot analysis of a panel of human livers indicates that the level of the 49 kDa protein, detected using antisera to either the mouse COH P-450 or rat P450IIA1 protein, correlates very highly with COH activity. 4. Antisera to the rat P450IIA1 protein can inhibit COH activity in human liver microsomes. Taken together, these data indicate that a member of the P450IIA subfamily is responsible for most, if not all, of the COH activity in human liver.

Purification of ethanolaminephosphotransferase from bovine liver microsomes

1999 ◽  
Vol 1437 (1) ◽  
pp. 80-92 ◽  
Author(s):  
Alessandra Mancini ◽  
Francesca Del Rosso ◽  
Rita Roberti ◽  
Pierluigi Orvietani ◽  
Lucia Coletti ◽  
...  
Keyword(s):  
Liver Microsomes ◽  
Bovine Liver
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