scholarly journals Fractionation and purification of hepatic microsomal cytochrome P-450 isoenzymes from phenobarbital-pretreated rats by h.p.l.c. A convenient tool for screening of isoenzymes inactivated by allylisopropylacetamide

1986 ◽  
Vol 239 (3) ◽  
pp. 661-669 ◽  
Author(s):  
L M Bornheim ◽  
M A Correia
Keyword(s):  
Ion Exchange ◽  
Column Chromatography ◽  
Resolving Power ◽  
Isolation And Purification ◽  
Microsomal Cytochrome ◽  
Promising Tool ◽  
Ion Exchange Column ◽  
Membrane Bound ◽  
Cytochrome P 450

A procedure incorporating the salient features of ion-exchange column chromatography with ion-exchange h.p.l.c. is described for the fractionation and purification to homogeneity of several membrane-bound rat hepatic phenobarbital (PB)-inducible cytochrome P-450 isoenzymes, including the major PB-inducible species. The resolving power of this technique makes it a highly promising tool for the isolation and purification of closely related cytochrome P-450 isoenzymes. In addition, it may also be used for screening of individual isoenzymes either selectively induced or repressed by a variety of endobiotics or xenobiotics. Accordingly, we have exploited this particular feature to identify not only the PB-inducible cytochrome P-450 isoenzymes destroyed in vivo by allylisopropylacetamide, a suicide inactivator of cytochrome P-450, but also to distinguish those that are reparable by exogenous haemin from those that are irreparably damaged.

scholarly journals AMINO ACID COMPOSITION AND ELECTROPHORETIC PROPERTIES OF HYPERTENSIN I

1955 ◽  
Vol 102 (4) ◽  
pp. 435-440 ◽  
Author(s):  
Leonard T. Skeggs ◽  
Walton H. Marsh ◽  
Joseph R. Kahn ◽  
Norman P. Shumway
Keyword(s):  
Amino Acids ◽  
Quantitative Analysis ◽  
Amino Acid ◽  
Ion Exchange ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Isoelectric Point ◽  
Column Chromatography ◽  
Isoleucine Leucine ◽  
Ion Exchange Column

A preparation of hypertensin I was purified by countercurrent distribution and was shown to migrate as a single component in starch blocks at pH 9.3 and 4.2. It had an isoelectric point of 7.7. Quantitative analysis by ion exchange column chromatography showed eight amino acids in approximately unimolar proportion: aspartic, proline, valine, isoleucine, leucine, tyrosine, phenylalanine, and arginine. There were in addition two moles of histidine.

Quantitative Method for Estimating Fecal Amino Acids

1975 ◽  
Vol 21 (10) ◽  
pp. 1437-1440 ◽  
Author(s):  
Christopher W I Owens ◽  
Walfredo Padovan
Keyword(s):  
Amino Acids ◽  
Ion Exchange ◽  
Column Chromatography ◽  
Quantitative Method ◽  
Normal Values ◽  
Amino Nitrogen ◽  
Exchange Column ◽  
Ion Exchange Column ◽  
Fresh Stool

Abstract We describe a method for quantitatively estimating 24 ninhydrin-reacting substances, including the commoner amino acids, in fecal dialysate prepared from ingested dialysis bags retrieved from fresh stool. It is accurate to 2 µmol of α-amino nitrogen per liter of fecal dialysate, and for most substances recovery of added standards is 100%. It involves dilution, ultrafiltration, and automated ion-exchange column chromatography of the dialysate. Some normal values are provided.

scholarly journals Regulation of cholesterol and bile acid homoeostasis in bile-obstructed rats

1991 ◽  
Vol 280 (2) ◽  
pp. 373-377 ◽  
Author(s):  
S Dueland ◽  
J Reichen ◽  
G T Everson ◽  
R A Davis
Keyword(s):  
Bile Acid ◽  
Bile Duct ◽  
Liver Function ◽  
Urinary Excretion ◽  
Bile Acids ◽  
Bile Duct Ligation ◽  
Microsomal Cytochrome ◽  
Duct Ligation ◽  
Cytochrome P 450

We examined how total blockage of biliary excretion, the major pathway through which cholesterol and bile acids are removed from the body, affects liver function, cholesterol and bile acid metabolism and homoeostasis. After 4 weeks of bile-duct ligation, rats showed impaired liver function, as documented by elevations in serum bilirubin and alkaline phosphatase activity. Moreover, bile-duct ligation decreased by about 30% both the amount of microsomal cytochrome P-450 in the liver and the elimination of aminopyrine in vivo, a reliable index in vivo of microsomal mixed-function oxidase activity. Cholesterol and bile acid contents in livers of bile-duct-ligated rats were doubled compared with sham-operated controls. Despite the increase in the contents of cholesterol and bile acids in liver, activities of the respective rate-limiting enzymes, 3-hydroxy-3-methylglutaryl-CoA reductase and cholesterol 7 alpha-hydroxylase, were doubled. Serum concentrations of bile acids and free cholesterol increased 25- and 4-fold respectively. The large increase in serum bile acids was associated with a 380-fold increase in the urinary excretion of bile acids. Although there is a general decrease in cytochrome P-450 content and drug metabolism involving cytochrome P-450-containing hydroxylases, the activity of cholesterol 7 alpha-hydroxylase, also a cytochrome P-450-containing enzyme, is actually increased. These data show that complete obstruction of the bile duct results in the selective impairment of microsomal cytochrome P-450. Increased activity of 7 alpha-hydroxylase, bile acid synthesis and urinary excretion provides an alternative excretory pathway that helps to maintain cholesterol homoeostasis when the biliary excretory pathway is eliminated.

Cytochrome P-450 and Peroxidase Oxidize Detoxication Products of Carcinogenic Aristolochic Acids (Aristolactams) to Reactive Metabolites Binding to DNA in vitro

1995 ◽  
Vol 60 (12) ◽  
pp. 2189-2199 ◽  
Author(s):  
Marie Stiborová ◽  
Eva Frei ◽  
Heinz H. Schmeiser ◽  
Manfred Wiessler
Keyword(s):  
Dna Adducts ◽  
Microsomal Cytochrome ◽  
Aristolochic Acids ◽  
Nuclease P1 ◽  
Order Of Magnitude ◽  
Prostaglandin H ◽  
Cytochrome P 450

We report the analysis of DNA adducts formed from aristolactams I and II, which are the final metabolites derived from carcinogenic aristolochic acids in vivo, after their oxidation by microsomal cytochrome P-450 and horseradish peroxidase in vitro. DNA adducts were detected and quantified using the nuclease P1-enhanced variation of the 32P-postlabeling assay. Quantitative analysis revelead that the extent of modification of DNA by aristolactams activated by peroxidase was more than one order of magnitude higher than for activation by microsomal cytochrome P-450. Peroxidase catalyzes the formation of active oxygen in the presence of NADH, H2O2 and aristolactams. Aristolactams are also oxidized by mammalian peroxidase prostaglandin H synthase. The possible role of aristolactams in carcinogenesis induced by aristolochic acid is discussed.

Induced binding of proteins by ammonium sulfate in affinity and ion-exchange column chromatography

2007 ◽  
Vol 70 (3) ◽  
pp. 493-498 ◽  
Author(s):  
Tsutomu Arakawa ◽  
Kouhei Tsumoto ◽  
Daisuke Ejima ◽  
Yoshiko Kita ◽  
Yasushi Yonezawa ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Ammonium Sulfate ◽  
Column Chromatography ◽  
Exchange Column ◽  
Ion Exchange Column
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