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Biomedical subjects

N F Taylor

Publications and source records attributed to N F Taylor.

At least 91 records · Page 5Linked to original sources
PubMed1977

A comparison between the lecithin/sphingomyelin ratio and the Nile blue sulphate test in the estimation of fetal maturity.

Functional fetal maturity was assessed in 72 patients by measuring in amniotic fluid the lecithin/sphingomyelin ratio and the differential cell count. The correlation between these two tests is presented. Only one fetus with a lecithin/sphingomyelin ratio of 2 or more developed the respiratory distress syndrome after delivery: that was the child of a diabetic mother. The technical limitations of the lecithin/sphingomyelin ratio meant that it could not be measured in 12% of samples obtained.

Adult↗
PubMed1975

The specificity of oxidase and kinase preparations from Pseudomonas fluorescens towards deoxyfluoromonosaccharides.

With partially purified enzyme preparations from cell-free extracts of Pseudomonas fluorescens, 3-deoxy-3-fluoro-D-glucose and 3-deoxy-3-fluoro-D-gluconic acid are substrates for glucose oxidase (EC 1.1.3.4.) and gluconate dehydrogenase (EC 1.1.99.3), with K-m values 18.2 mM and 11.8 mM, respectively. The same enzymes that oxidize glucose and gluconic acid probably oxidize 3-deoxy-3-fluoro-D-glucose and 3-deoxy-3-fluoro-D-gluconic acid. The latter fluorinated carbohydrates and the presumed formation of 3-deoxy-3-fluoro-2-keto-D-gluconic acid, which has been isolated as a calcium salt and characterizied, are not substrates for gluconokinase (EC 2.7.1.12). Both 3-deoxy-3-fluoro-D-glucose and 3-deoxy-3-fluoro-D-gluconic acid act as competitive inhibitors of this enzyme preparation for gluconate, with K-i values 47.5 mM and 14.8 mM, respectively.

Alcohol Oxidoreductases↗
PubMed1975

A model for the mode of action of cytochalasin B inhibition of D-glucose transport in the human erythrocyte.

By an optical method, cytochalasin B is shown to be a competitive inhibitor of D-glucose transport across the human erythrocyte membrane with Ki of 1.2 x 10(-7) M. A Drieding molecular model of cytochalasin B reveals an almost identical spatial distribution of four oxygen atoms to those found in the C1-conformation of beta-D-glucopyranose and implicated in hydrogen bonding to the carrier protein associated with D-glucose transport. The stereochemistry of this transport model is discussed. On the basis of the interoxygen distances found in cytochalasin B, hydrocortisone, prednisolone, corticosterone, and phenolphthalein are considered as analogues and are shown to be competitive inhibitors of D-glucose transport with Ki values of 2.2 x 10(-4) M, 3.0 x 10(-4) M, 4.0 x 10(-4) M, and 2.5 x 10(-5) M, respectively. These results are considered to be consistent with the proposed mode of action of cytochalasin B and also provide further support for the model of D-glucose stereospecifically hydrogen-bonded to a carrier protein.

Binding Sites↗
PubMed1973

The interaction of 3-deoxy-3-fluoro-D-glucose with the hexose-transport system of the human erythrocyte.

1. By using an optical method the kinetic parameters of hexose transport across the human erythrocyte membrane were determined for several sugars. The series of half-saturated constants is as follows: 3-deoxy-3-fluoro-d-glucose = 3-O-methyl-d-glucose <d-glucose<d-mannose <3-deoxy-d-glucose<d-galactose<l-arabinose. 2. Estimations of the dissociation energy of the 3-deoxy-3-fluoro-d-glucose-carrier and d-glucose-carrier complexes suggest that the binding of the two sugars to the transport system is equivalent. 3. Incubation of the erythrocytes with 3-deoxy-3-fluoro-d-glucose results in a small but significant release of F(-) anion. Cells treated in this way lose their ability to transport glucose.

Arabinose↗
PubMed1972

Activity of fluoro and deoxy analogues of glycerol as substrates and inhibitors of glycerol kinase.

Analogues of glycerol in which each of the three hydroxy groups is successively replaced by fluorine or hydrogen have been examined as substrates or inhibitors of glycerol kinase (Candida mycoderma) to assess the ability of fluorine to mimic a substrate hydroxy group in enzyme-analogue interactions. The four diols resulting from replacement of the hydroxy groups at C-1 or C-2 of sn-glycerol by fluorine or hydrogen are weak substrates. Similar substitution of the C-3 hydroxy group gives compounds which act as competitive inhibitors of glycerol or dihydroxyacetone phosphorylation but show no activity as substrates. Comparison of the steady-state kinetic parameters of the corresponding analogues shows that replacement of a hydroxy group by either fluorine or hydrogen leads to compounds with similar activity in this system. A convenient synthesis of (+)-propane-1,2-diol is described.

Candida↗