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Biomedical subjects

J E Kinsella

Publications and source records attributed to J E Kinsella.

11 recordsLinked to original sources
PubMed1978

Control of phosphatidylcholine synthesis and the regulatory role of choline kinase in rat liver. Evidence from essential-fatty acid-deficient rats.

Choline kinase and phosphocholine cytidylytransferase catalyse the rate-limiting steps of the cytidine pathway for the synthesis of phosphatidylcholine [Infante (1977) Biochem. J. 167, 847--849]. Essential-fatty acid deficiency induces a 3.5-fold increase in the specific activity of choline kinase, whereas the specific activity of the cytidylytransferase remains unchanged in rat liver. This change in specific activity accounts for the calculated increase in flux through the cytidine pathway produced in vivo by the same dietary state [Trewhella & Collins (1973 Biochim. Biophys. Acta 296, 34--50], thus confirming the fact that choline kinase has a regulatory role in the cytidine pathway for the synthesis of phosphatidylcholine.

Animals↗
PubMed1978

Effect of thiol reagents on extractability of protein from yeast.

The effect of soluble thiol reagents on the extractability of protein from yeast cells was studied. The incubation of yeast cells with dithiothreitol, 2-mercaptoethanol, or monothioglycerol markedly stimulated the release of soluble carbohydrates into the medium. There was a concomitant improvement (over twofold) in the extractability of protein from the yeast cells. The thiol reagents activated the proteolytic enzymes of the yeast cells. Unless inactivated, these enzymes hydrolyze the extracted protein.

Fungal Proteins↗
PubMed1978

Yeast proteins: recovery, nutritional and functional properties.

The future need for supplementary sources of food grade functional proteins is emphasized and the potential role of yeasts as a source of proteins is discussed. The problems of proteolysis and nucleic acid contamination can be circumvented by succinylation or derivatization of the yeast protein during extraction. Succinylated yeast proteins demonstrate improved functional properties though their nutritional value needs to be investigated.

Candida↗
PubMed1978

Texturized proteins: fabrication, flavoring, and nutrition.

This paper provides a comprehensive review of the current methods used for the texurization of proteins, with emphasis on soy proteins. The sensory characteristics, i.e., flavor, texture, and color are discussed, particularly in relation to the problems of simulating meat flavored products. The nutritional qualities of texturized products are reviewed, and current regulations concerning their use in foods are cited.

Amino Acids, Essential↗
PubMed1978

Orange juice quality with an emphasis on flavor components.

This review studies the chemistry of the flavor of citrus juices with emphasis on the components of the flavor of orange juice and their origin in the different parts of the orange fruit. Citrus processing and the nature of the various products as they affect flavor are discussed. The composition of peel oil, aroma oil, orange juice, orange essence, and orange essence oil is presented. The relationship between flavor and color are discussed and the role of lipid components as they affect flavor stability and off-flavors are described. Spoilage resulting from microbes is briefly treated. The nutritional value of orange juice is cited.

Beverages↗
PubMed1976

Phospholipid synthesis in mammary tissue. Choline and ethanolamine kinases: kinetic evidence for two discrete active sites.

Choline and ethanolamine kinases are located in the high speed supernatant of lactating bovine mammary gland. Maximum activities of choline and ethanolamine kinases were observed at pH 9.2 and 8.0, respectively, with the rate of ethanolamine phosphorylation being 1/15 that of choline phosphorylation. Activation energies of 29 joules (Q10--1.5) and 31 joules (Q10 = 1.5) were calculated between 3.4 and 31.3 C for choline kinase and ethanolamine kinase, respectively. Above 31.3 C, the Arrhenius plot deviated from linearity for both enzymes, suggesting that denaturation was occurring. An apparent Km of 0.25 mM for choline was obtained for choline kinase activity. The apparent Km of ethanolamine kinase for ethanolamine was unusually high (17 mM), the activity was not linear with increasing protein concentration. Activity was tripled and the Km decreased to 2.5 mM when the enzyme preparation was washed with butanol: benzene mixture, suggesting the presence of an endogenous competitive inhibitor(s), with respect to ethanolamine. Choline kinase was not affected by the solvent wash. Substrate competition studies revealed that choline kinase was slightly inhibited competitively by ethanolamine (apparent Ki = 19-21 mM), whereas choline was a potent competitive inhibitor of ethanolamine kinase (apparent Ki = 0.33-0.50 mM). The results indicated that these two kinase activities were mediated by two distinct active sites, possibly on a single protein. The significance of choline in the regulation of phosphatidylethanolamine synthesis is discussed.

Animals↗
PubMed1976

Enzymes of Penicillium roqueforti involved in the biosynthesis of cheese flavor.

The ripening of blue and Roquefort cheeses is accomplished by the concerted and controlled actions of enzymes of the mold Penicillium roqueforti. The properties and effects of the enzymes involved in flavor development (i.e., proteases, lipase and beta-ketoacid decarboxylase) are reviewed. The metabolic activities of both spores and mycelia of P. roqueforti in relation to fatty acid metabolism and flavor generation are discussed. The chemical composition of blue cheese flavor and the simulation of this flavor by fermentation and formulation are briefly surveyed. Some nutritional aspects of blue cheese are cited.

Alkanes↗