H L Kersters-Hilderson

Learn More
The binding of two activating cations, Co2+ and Mg2+, and of one inhibitory cation, Ca2+, to D-xylose isomerase from Streptomyces violaceoruber was investigated. Equilibrium-dialysis and spectrometric studies revealed that the enzyme binds 2 mol of Co2+/mol of monomer. Difference absorption spectrometry in the u.v. and visible regions indicated that the(More)
D-Xylose isomerases are metal-ion (Mn2+, Co2+, Mg2+)-requiring tetrameric enzymes. Both the stoichiometry and the binding constants have been determined by titrating the metal-ion-free enzymes from five organisms (Actinomycetaceae and more divergent bacteria) with the respective metal ions using the enzyme activity as indicator of active complex-formation.(More)
Bacillus pumilus beta-D-xylosidase, purified by affinity chromatography, seems to be homogeneous, as judged by disc electrophoresis and gel filtration. The absorption coefficient at 280 nm, Ao, 1% 1cm, determined by the dry weight method, is 1.78. The complete amino acid composition is determined. Sedimentation velocity studies show the presence of two(More)
The influence of substituents on the binding and hydrolysis of several substituted beta-D-xylopyranosides by beta-D-xylosidase from Bacillus pumilus PRL B12 has been investigated. From a comparison of the inhibition constants of 1-thio-beta-D-xylopyranosides with the apparent Michaelis-Menten constants of the substrates, it followed that the latter(More)