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G J Kelly

Publications and source records attributed to G J Kelly.

8 recordsLinked to original sources
PubMed1978

Purification and properties of spinach leaf cytoplasmic fructose-1,6-bisphosphatase.

Cytoplasmic fructose-1,6-bisphosphatase has been purified from spinach leaves to apparent homogeneity. The enzyme is a tetramer of molecular weight about 130,000. At pH 7.5, the Km for fructose 1.6-bisphosphate was 2.5 micron, and for MgCl2 0.13 mM; the enzyme was specific for fructose 1,6-bisphosphate. Saturation with Mg2+ was achieved with lower concentrations at pH 8 than at pH 7. AMP and high concentrations of fructose 1,6-bisphosphate inhibited enzyme activity. Ammonium sulfate relieved the latter inhibition but was itself inhibitory when substrate concentrations were low. Acetylation studies demonstrated that the AMP regulatory site was distinct from the catalytic site. Cytoplasmic fructose-1,6-bisphosphatase may contribute to the regulation of sucrose biosynthesis in plant leaves.

Cytoplasm↗
PubMed1977

Comparison of non-biospecific effects in immunoaffinity chromatography using cyanogen bromide and bifunctional oxirane as immobilising agents.

Polypeptide antigen, glucagon, antibodies to glucagon and non-immune globulins were immobilised on agarose using CNBr and a bifunctional oxirane. Irrespective of the ligand immolilised, positively charged groups introduced to conjugates by CNBr caused electrostatic interactions with impurities and soluble biospecific ligands. Solvents required for elution of bound antibodies and antigens were more strongly deforming when immunoaffinity conjugates were prepared with CNBr than with the oxirane. This is attributed to compound affinity resulting from reinforcement of biospecific by non-biospecific interactions. Strongly deforming solvents were still required for oxirane conjugates, however, when antibodies had high affinity for antigen.

Antibodies↗
PubMed1976

Efficient purification and molecular properties of spinach chloroplast fructose 1,6-bisphosphatase.

A relatively straightforward procedure has been developed for the purification of chloroplast fructose bisphosphatase from spinach leaves to apparent homogeneity and with 80% yield. The molecular weight of the enzyme was about 160 000. Chloroplast fructosebisphosphatase consists of four possibly identical subunits and, at pH 8.8, EASILY DISSOCIATES INTO EQUAL HALVES WITH LOWered activity. Sigmoid saturation curves with Hill coefficients between 3.0 and 3.7 were obtained for fructose 1,6-bisphosphate and Mg2+. Incubation of the enzyme with 20 mM dithiothreitol slowly altered the response to pH from no activity measured at pH 7.5 and full activity at pH 8.8 to equal activity at each of these pH values; at the same time the number of freely available sulphydryl groups increased from four to twelve per molecule. These properties are considered in the context of the observed activation of this enzyme following illumination of chloroplasts.

Chloroplasts↗