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Biomedical subjects

G F Bryce

Publications and source records attributed to G F Bryce.

35 records · Page 2Linked to original sources
PubMed1977

Insulin and glucagon: plasma levels and pancreatic release in the genetically obese Zucker rat.

Circulating levels of insulin and glucagon, as well as their release from isolated pancreatic islets, have been measured in Zucker rats to examine the effect of genotype, sex and diet. The obese animals had higher plasma insulin levels and enhanced release from islets when compared to lean controls. Conversely, obese animals, despite no significant differences in fed plasma levels of glucagon, showed substantially reduced release from islets. Diet had no main effect on any of these parameters.

Animals↗
PubMed1973

Studies on the enzymes involved in the biosynthesis of cyclo-tris (N-2,3-dihydroxybenzoyl-L-seryl) in Escherichia coli: kinetic properties of the L-serine-activating enzyme.

Some kinetic properties of the formation of a thioester-bound l-seryl-enzyme intermediate are described. The rate constant of formation is 3.12 x 10(2) M(-1) s(-1) and the rate constant for spontaneous breakdown is 2.47 x 10(-3) s(-1). These constants yield a value of log K = 5.10 for the overall equilibrium constant which agrees favorably with a value of 5.20 calculated from equilibrium binding data. E(1).serine formation requires a thiol group which is extremely reactive to N-ethylmaleimide; the second-order rate constant for enzyme inactivation by this reagent is 77.1 M(-1) s(-1) at pH 6.6 and 0 C. Excess l-serine does not protect the enzyme against inactivation. In addition to an adenosine triphosphate-[(32)P]-inorganic pyrophosphate exchange, the enzyme also catalyzes an l-serine-dependent adenosine triphosphate-[(3)H]adenosine monophosphate exchange in accordance with the scheme proposed for the activation of serine.

Adenosine Monophosphate↗