Cholesterol has been used to monitor artifact generation. Stability differences among cholesterol oxide products (COPs) and cholesterol in thermal and alkaline conditions are theorized. Thus, use of cholesterol may be unsuitable for detection of artifacts generated from COPs. Stability of cholesterol was compared to that of 7-ketocholesterol (7-keto) and β-sitosterol (βS) under various thermal ...

Endothelial dysfunction and a sedentary lifestyle may be involved in the development of hypertension which is proliferative among middle-aged African Americans (AA). Signaling molecules derived from the oxidation of 20-carbon fatty acid molecules known as eicosanoids influence vascular tone. The relationship between aerobic fitness and eicosanoid formation following exercise in middle-aged Afri...

The effects of the peptidoleukotrienes C4 (LTC4), D4 (LTD4), E4 (LTE4) and a series agonists and antagonists on arachidonic acid metabolism were characterized in minced guinea pig lung. In response to LTD4, guinea pig lung utilized and converted the endogenous arachidonic acid into a variety of cyclooxygenase metabolites [prostaglandins (PGs) E2, F2 alpha, 6-keto-F1 alpha and thromboxane (Tx) B...

For the catabolism of D-glucuronate, different pathways are used by different life forms. The pathways in bacteria and animals are established, however, a fungal pathway has not been described. In this communication, we describe an enzyme that is essential for D-glucuronate catabolism in the filamentous fungus Aspergillus niger. The enzyme has an NADH dependent 2-keto-L-gulonate reductase activ...

Lipoic acid-dependent pathways of alpha-keto acid oxidation by mitochondria were investigated in pea (Pisum sativum), rice (Oryza sativa), and Arabidopsis. Proteins containing covalently bound lipoic acid were identified on isoelectric focusing/sodium dodecyl sulfate-polyacrylamide gel electrophoresis separations of mitochondrial proteins by the use of antibodies raised to this cofactor. All th...

abstract:turmeric is a member of the ginger family (zingiberaceae), which is extensively used as a spice, food preservative and colouring material. curcumin is a main bioactive natural compound derived from the rhizome of this plant. curcumin can exist in several tautomeric forms, keto and enol. the keto form is more stable than enol form. silyl ethers have proven to be versatile substrates for...

4-Aryl-4-oxoesters undergo facile reduction of both the keto and the ester groups with methanolic NaBH₄ at room temperature to yield the corresponding 1-aryl-1,4-butanediols whereas 4-alkyl-4-oxoesters furnish the corresponding 1,4-butanolides via selective reduction of the keto moiety. Results of a detailed and systematic investigation of the reaction are described.

(S(a))-Binam-D-prolinamide (20 mol%), instead of (S(a))-binam-L-prolinamide, in combination with chloroacetic acid (100 mol%) is an efficient organocatalyst for the direct aldol reaction between α-keto esters as electrophiles and alkyl and α-functionalised ketones, under quasi solvent-free conditions, providing access to highly functionalised chiral quaternary γ-keto α-hydroxyesters with up to ...

Many of the amino acids required in the diet of animals or microorganisms are non-essential if the corresponding keto acids are supplied (cf. (l-7)). How these keto acids are transformed to amino acids in viva is not generally known, but the change is assumed to occur either by reductive amination or by transamination. The transaminating enzymes so far studied all require pyridoxal phosphate as...