Oxidative and hydrolytic degradation reactions were carried out on teicoplanin in order to characterize the aromatic portion of the molecule and relate it to the other members of the class of glycopeptide antibiotics. Seven aromatic rings, obtained as triphenyl ether, diphenyl ether, and diphenyl moieties after oxidation nd hydrolysis of teicoplanin, were identified. They are present in teicopl...

A cell line of Eschscholtzia californica selected for meta-fluorotyrosine (MFT) tolerance was found to have 10-fold increased levels of phenylalanine and tyrosine compared to the parent line, while most other amino acids were only increased 2-fold. Tracer experiments with shikimic acid in the presence of MFT showed that the biosynthesis of the aromatic amino acids was not impaired in the tolera...

The aim of the present work is to study the chemical composition of Turkish propolis. Propolis samples were collected from different regions of Turkey (Bursa, Erzurum-Askale, Gumushane-Sogutagil and Trabzon-Caglayan) in 1999. Ethanol extracts of propolis (EEP) were prepared for chemical analysis, using gas chromatograph coupled with mass spectrometry (GC-MS). Our findings show that propolis sam...

Concentrations of organic acids in prebiotic soils were presumably low, given limitations in abiotic synthesis and the limited lifetimes of organic molecules before the ultraviolet shield developed on early Earth. Prokaryotes, the first landcolonizing organisms, commonly secrete aliphatic carboxylic acids, and, less extensively, secrete aromatic compounds as siderophores and antibiotics. In con...

A quantitative capillary assay was used to show that aromatic acids, compounds that are chemorepellents for Escherichia coli and Salmonella sp., are chemoattractants for Pseudomonas putida PRS2000. The most effective attractants were benzoate; p-hydroxybenzoate; the methylbenzoates; m-, p-, and o-toluate; salicylate; DL-mandelate; beta-phenylpyruvate; and benzoylformate. The chemotactic respons...

Aspartate: 2-oxoglutarate aminotransferase from the anaerobic protozoon Trichomonas vaginalis was purified to homogeneity and characterized. It is a dimeric protein of overall Mr approx. 100000. Only a single isoenzyme was found in T. vaginalis. The overall molecular and catalytic properties have features in common with both the vertebrate cytoplasmic and mitochondrial isoenzymes. The purified ...

Evidence is presented that aromatic ol-keto acid reductase accounts for at least 80% of the total activity responsible for the reduction of aromatic a-keto acids to their corresponding phenyllactic acids in mammalian tissues. The remaining activity can be attributed to lactic dehydrogenase, which is in keeping with the known broad substrate specificity of this enzyme. The relative contribution ...

The adsorption of chloro-aromatic acids to monomolecular layers of oat squashes is reported in earlier papers but it was not possible by the technique used, to measure unambiguously the adsorption of unsubstituted and 2,6-dichloro-aromatic acids. This has now been achieved by a modification of the earlier method and involves assessments of competitive adsorption between the unknown acid and a s...

Phenylacetic and hydroxyphenylacetic acids were present as major acids in spent growth medium from Clostridium botulinum type G. These aromatic acids were identified by gas-liquid chromatography and mass spectrometry.

a simple and efficient one-pot, three-component strecker reaction of protected amino acids, aromatic aldehydes, and trimethylsilyl cyanide has been developed for the synthesis of chiral α-amino nitriles. the reaction was carried out in the presence of catalytic amount of phosphotungstic acid (h3[p(w3o10)4]) as an environmentally friendly catalyst.