scholarly journals Studies on the biosynthesis of cholesterol. 9. Formation of phosphorylated derivatives of mevalonic acid in liver-enzyme preparations*

1959 ◽  
Vol 73 (3) ◽  
pp. 410-415 ◽  
Author(s):  
A. De Waard ◽  
G. Popják
Keyword(s):  
Liver Enzyme ◽  
Mevalonic Acid ◽  
Enzyme Preparations ◽  
Derivatives Of

Hydroxycinnamoyl: Coenzyme A Transferase Involved in the Biosynthesis of Kaempferol-3-(p-coumaroyl Triglucoside) in Pisum sativum

1977 ◽  
Vol 32 (9-10) ◽  
pp. 765-768 ◽  
Author(s):  
Marie H. Saylor ◽  
Richard L. Mansell
Keyword(s):  
Coenzyme A ◽  
Chemical Properties ◽  
Acyl Donor ◽  
Coumaric Acid ◽  
Enzyme Preparations ◽  
Naturally Occurring ◽  
Enzymatic Formation ◽  
Derivatives Of ◽  
Acid Esters ◽  
And Chemical Properties

Abstract The major flavonoids of Pisum are derivatives of kaempferol and quercetin, including both tri-glucosides and acylated triglucosides in which the acyl group is p-coumaric acid. Although hydroxy-cinnamic acid esters of flavonoids are common pigments in many plants, neither the enzymes nor the precursors involved in their biosynthesis have been demonstrated. We report here that crude enzyme preparations extracted from peas catalyze the transfer of the p-coumaroyl moiety of p-coumaroyl: Coenzyme A to kaempferol-3-triglucoside forming kaempferol-3-(p-coumaroyl triglucoside) as the acylated product. The reaction product has been vigorously shown to be identical to the naturally occurring kaempferol-3-(p-coumaroyl triglucoside) in both chromatographic and chemical properties. The enzymatic formation of the acylated derivative occurred only minimally when incubated with the cofactors required for carboxyl group activation (ligase) and maximally when incubated with p-coumaroyl : Coenzyme A as the acyl donor.

Reduction of 7-ketolithocholic acid by human liver enzyme preparations in vitro

1989 ◽  
Vol 256 (1) ◽  
pp. G67-G71
Author(s):  
Y. Amuro ◽  
W. Yamade ◽  
K. Kudo ◽  
T. Yamamoto ◽  
T. Hada ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Liver Enzyme ◽  
Chenodeoxycholic Acid ◽  
Human Liver ◽  
Potassium Phosphate ◽  
Gas Chromatography Mass Spectrometry ◽  
Potassium Phosphate Buffer ◽  
Sodium Potassium ◽  
Enzyme Preparations

The formation of chenodeoxycholic and ursodeoxycholic acids from 7-ketolithocholic acid by human liver preparations was examined in vitro. Liver preparations were incubated with 7-ketolithocholic acid at pH 5.5 in a sodium-potassium-phosphate buffer containing NADPH or NADH. The products formed were analyzed by gas chromatography and gas chromatography-mass spectrometry. Results showed that chenodeoxycholic and ursodeoxycholic acids could be formed from 7-ketolithocholic acid by human liver enzyme(s). The enzyme(s) required NADPH but not NADH as coenzyme and was localized largely in the microsomes. The conjugated 7-ketolithocholic acid, especially the taurine conjugated, was predominantly reduced to chenodeoxycholic acid, whereas the unconjugated 7-ketolithocholic acid was not reduced well to either chenodeoxycholic acid or ursodeoxycholic acid. Thus the reduction of 7-ketolithocholic acid by human liver enzyme(s) was found to be dependent on whether the substrate was conjugated or not.

Further studies on ε-lysine acylase. The ω-N-acyl-diamino acid hydrolase activity of avian kidney

1968 ◽  
Vol 46 (5) ◽  
pp. 471-475 ◽  
Author(s):  
Jean Leclerc ◽  
Leo Benoiton
Keyword(s):  
Hydrolase Activity ◽  
Acid Hydrolase ◽  
Enzyme Preparations ◽  
Kidney Enzyme ◽  
Diamino Acid ◽  
Avian Kidney ◽  
Derivatives Of ◽  
Hog Kidney

ω-N-Acyl-diamino acids have been tested as substrates for ε-lysine acylase from animal sources. Chicken and pigeon kidney enzyme preparations hydrolyzed derivatives of lysine homologues as well as of lysine, the best substrates tested being ε-N-propionyl-lysine and ε-N-propionyl-ornithine. A modified procedure for purifying the enzyme from rat and hog kidney is presented. Some of its properties are different from those previously reported.

scholarly journals STUDY ON THE SITE OF BIOSYNTHESIS OF β-GLUCURONIDASE AND ITS APPEARANCE IN LYSOSOME IN NORMAL AND HYPOXIC RATS

1970 ◽  
Vol 18 (8) ◽  
pp. 529-541 ◽  
Author(s):  
JULIEN L. VAN LANCKER ◽  
PATRICK L. LENTZ
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Liver Enzyme ◽  
Rat Liver ◽  
Microsomal Enzymes ◽  
Enzyme Preparations ◽  
Lysosomal Fraction ◽  
Regenerating Rat Liver ◽  
Cell Fractions

For the purpose of investigating the site of synthesis of β-glucuronidase, the enzyme was purified, after injection of labeled amino acids, from various cell fractions of regenerating rat liver. Enzyme preparations purified from microsomal, lysosomal, mitochondrial, nuclear and supernatant fractions had identical catalytic and electrophoretic properties. In nonhypoxic rats, incorporation was detectable only in the microsomal enzymes and maximum labeling occurred 30 min after the injection of the labeled amino acid. No label was detectable in the enzyme purified from the lysosomal fraction of nonhypoxic animals. Labeling of enzyme purified from lysosomal fraction was, however, significant after 2 hr of hypoxia.

Effects of Metal Poisoning on Five Liver Enzymes in the Killifish (Fundulus heteroclitus)

1970 ◽  
Vol 27 (2) ◽  
pp. 383-390 ◽  
Author(s):  
Eugene Jackim ◽  
Janice M. Hamlin ◽  
Stephen Sonis
Keyword(s):  
Alkaline Phosphatase ◽  
Enzyme Activity ◽  
Xanthine Oxidase ◽  
Liver Enzyme ◽  
Fundulus Heteroclitus ◽  
Liver Enzymes ◽  
Enzyme Preparations ◽  
Liver Enzyme Activity ◽  
Acid And Alkaline Phosphatase ◽  
Metal Poisoning

Activities of five liver enzymes (acid and alkaline phosphatase, catalase, xanthine oxidase, and ribonuclease) from Fundulus heteroclitus surviving exposure to 96-hr TLm concentrations of salts of six metals (lead, copper, mercury, beryllium, cadmium, and silver) differed markedly from those of unexposed fish. Changes in enzyme activity produced by the exposures were not necessarily the same in magnitude or direction as those observed when the salts were introduced directly into the enzyme preparations. It is proposed that changes in liver enzyme activity may be useful as a kind of biochemical autopsy tool for diagnosing sublethal metal poisoning in fish.

scholarly journals Acetylation of serotonin in vitro by a human N-acetyltransferase

1969 ◽  
Vol 113 (4) ◽  
pp. 721-725 ◽  
Author(s):  
Thomas A. White ◽  
John W. Jenne ◽  
David A. Price Evans
Keyword(s):  
Genetic Polymorphism ◽  
Liver Enzyme ◽  
Human Liver ◽  
Natural Substrate ◽  
Enzyme Preparations ◽  
Wide Variability ◽  
Human Livers

1. There is a well-recognized genetic polymorphism for the N-acetylation of isoniazid and sulphamethazine by human livers. 2. Serotonin was found to be acetylated by human liver enzyme preparations and the N-acetylserotonin formed was identified and determined quantitatively. 3. In 13 livers examined there was a wide variability in the capacity to acetylate serotonin that did not correlate with the capacity of the same livers to acetylate isoniazid and sulphamethazine. The results suggest that serotonin is not a natural substrate for the polymorphic N-acetyltransferase and that it may be acetylated by a different enzyme.

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