Binding studies of L-usnic acid to D-fructose-6-P aminotransferase.
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Bacterial Proteins↗
Biomedical subjects
B Cifuentes
Publications and source records attributed to B Cifuentes.
L-usnate-urease interactions: binding sites for the ligand.
L-usnic acid inactivates urease by formation of high molecular weight aggregates which can reached by a maximum of 880 000. L-cysteine partially reverses the inactivation of stimulating the appearance of active high molecular weight polymers. The existence of two class of binding points for L-usnic acid on the urease molecule is proposed, the first showing high affinity for the ligand, related with the loss of activity, and the second, of low affinity, related to polymerization process.
Benzofurans↗
Purification and properties of glucosaminephosphate isomerase of Proteus mirabilis.
A glucosamine-P isomerase has been identified in Proteus mirabilis. The 113-fold purified enzyme exhibits a pH optimum of 7.5 with a secondary maximum at 8.5 and a temperature optimum at 37 degrees C. The apparent Km was 13.3 mM for fructose-6-P and 18.8 mM for L-glutamine. Molecular weight of the enzyme has been estimated as 120 000 and the protein can be dissociated in four subunits by SDS-polyacrylamide electrophoresis.
Carbohydrate Epimerases↗
L-usnate-urease interactions: binding sites for polymerization.
L-usnic acid inactivates urease through a process which implicates the blockade of--SH groups in parallel to the formation of inactive polymers. Both L-alanine and L-proline partially reverses the inactivation and effectively diminishes the amount of highly polymerized protein. The amino acids also prevent the linkage of L-usnic acid on the sites of low affinity for the ligand, being then related to the sites of polymerization.
Alanine↗