ABSTRACT
Experiments with D-glucose-6-P stereospecifically tritiated at C-6 showed that the myo-inositol-1 P synthase reaction catalyzed by both the enzyme from beef testis and from pollen of Lilium longiflorum proceeds with stereospecific loss of the pro-6R and incorporation of the pro-6S hydrogen into the product. The ring closure thus occurs in a retention mode at C-6 of the substrate, a finding at variance with an earlier report, but in agreement with the stereochemistry recently determined for the reaction in Streptomyces flavopersicus and with the general stereochemical mode of operation of aldolases.
Subject(s)
Carbohydrate Epimerases/metabolism , Myo-Inositol-1-Phosphate Synthase/metabolism , Plants/enzymology , Testis/enzymology , Animals , Carbon Radioisotopes , Cattle , Deuterium , Glucosephosphates , Male , Radioisotope Dilution Technique , Substrate Specificity , TritiumABSTRACT
Chitin synthase from Coprinus cinereus (Schaeff. ex Fr.) S. F. Gray (= C. lagopus sensu Buller) was used as a model for chitin synthase from insects. The effect of dimilin (difluorobenzuron), captan (trichloromethylsulfonyl fungicide), kitazin P (organophosphorus ester fungicide) and parathion (organophosphorus insecticide) on the fungal enzyme was compared with the effect of nikkomycin (nucleosidepeptide antibiotic).
Subject(s)
Agaricales/enzymology , Anti-Bacterial Agents/pharmacology , Chitin Synthase/antagonists & inhibitors , Coprinus/enzymology , Fungicides, Industrial/pharmacology , Glucosyltransferases/antagonists & inhibitors , Insect Control , Insecticides/pharmacology , Captan/pharmacology , Diflubenzuron/pharmacology , Drug Evaluation, Preclinical , Models, Chemical , Nucleosides/pharmacology , Parathion/pharmacologyABSTRACT
In the course of a screening for new metabolites from fungi we isolated a substance with antimicrobial activity from cultures of Aspergillus duricaulis (CBS 481.65) (Tü 679). It was antagonized by putrescine, spermidine, spermine, arginine, citrulline, lysine, ornithine, in higher concentration by aspraagine and glutamine too. The effect of ethylenediaminetetraacetate on the susceptibility of Streptomyces viridochromogenes (Tü 57) and Bacillus subtilis ATCC 6051 to this antibiotic has been studied. The substance was characterized and identified as cyclopaldic acid.
Subject(s)
Anti-Bacterial Agents/biosynthesis , Aspergillus/metabolism , Benzofurans/biosynthesis , Amino Acids/pharmacology , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Bacillus subtilis/drug effects , Bacillus subtilis/metabolism , Benzofurans/isolation & purification , Benzofurans/pharmacology , Chemical Phenomena , Chemistry , Drug Antagonism , Edetic Acid/pharmacology , Fermentation , Polyamines/pharmacology , Streptomyces/drug effectsABSTRACT
The stereochemical course of the dTDP-glucose oxidoreductase (EC 4.2.1.46) reaction was studied using enzyme partially purified from Escherichia coli and dTDP-(6R)- and (6S)-[4-2H, 6-3H]glucose as substrate. The latter was prepared enzymatically by reduction of (3R)- and (3S)-3-P-[3-3H]glycerate to the 1-deuterated 3-P-glyceraldehyde with (4S)-[4-2H]NADH, followed first by conversion to glucose-1-P with the glycolytic enzymes, and then by transformation into the dTDP derivative. The stereospecifically labeled dTDP-glucose samples were mixed with nonlabeled carrier material and converted to dTDP-4-keto-6-deoxyglucose, which contained a chiral methyl group as shown by chirality analysis of the acetic acid resulting from Kuhn-Roth oxidation of the sugar nucleotide. These results confirm that the hydrogen transfer from C4 to C6 is intramolecular and show that the migrating hydrogen replaces the 6-hydroxyl group with inversion of configuration. Assuming that the hydrogen transfer, since it is intramolecular, must be suprafacial, it follows that the elimination of water from C5 and C6 is formally syn, whereas the reduction of the resulting delta5,6-double bond formally involves an anti addition of H+ and H-.
