The silica-based Fe(III)-protoporphyrin and Zn-tetraphenylporphyrin stationary phases were examined for the HPLC separation of anions. The retention of nine common inorganic anions as well as benzoate anion (BA) and its hydroxy analogues (HBA) was examined using tartrate, acetate, and succinate eluents. The retention factors of inorganic anions on the FeProP stationary phase were in the order C...

During the catalytic reactions of flavoprotein hydroxylases and bacterial luciferase, flavin peroxides are formed as intermediates [see Massey, V. and Hemmerich, P. (1976) in The Enzymes, 3rd edn (P. Boyer, ed.) pp. 421--505, Academic Press, New York]. These intermediates have been postulated to be C(4a) derivatives of the flavin coenzyme. To test this hypothesis, modified flavin coenzymes carr...

Antifungal caspofungin (CPFG) was approved for the treatment of febrile neutropenia (FN) as the empiric treatment. However, the relationship between pharmacokinetic properties of CPFG and its clinical effects in patients with FN has not been fully established yet. Thus, in the present study, we tried to establish the simple and quantitative HPLC method to measure CPFG in human plasma with liqui...

p-Hydroxybenzoate hydroxylase (EC 1.14.13.2) from Pseudomonas desmolytica is known to form a stable complex with its substrate. Investigations were made on properties of the complex by spectrophotometric measurements and photooxidation. The addition ofp-hydroxybenzoate or benzoate to the oxidized (with respect to bound FAD) enzyme solution caused changes in absorption, fluorescence, and CD spec...

The enzymatic formation of p-hydroxybenzoate from p-coumarate in cell-free extracts of cell cultures of Lithospermum erythrorhizon Sieb. et Zucc. was investigated. p-Coumaroyl-coenzyme A (p-coumaroyl-CoA) is the activated intermediate in this biosynthetic reaction. It is formed by an ATP-, Mg2+ -, and CoA-dependent 4-hydroxycinnamate:CoA ligase reaction. p-Coumaroyl-CoA is oxidized and cleaved ...

Methyl p-hydroxybenzoate (methylparaben) is one of the most important pharmaceutical preservatives. The determination of methylparaben in multi-component pharmaceutical preparations is complicated by the fact that its total concentration seldom exceed 0.1% of the formulation. The possibility that it can interact chemically with active ingredients’ led to a need for a rapid and reliable quantita...

This work reports the development of an amperometric glucose-6-phosphate biosensor by coimmobilizing p-hydroxybenzoate hydroxylase (HBH) and glucose-6-phosphate dehydrogenase (G6PDH) on a screen-printed electrode. The principle of the determination scheme is as follows: G6PDH catalyzes the specific dehydrogenation of glucose-6-phosphate by consuming NADP(+). The product, NADPH, initiates the ir...

Carbon catabolite repression is an important mechanism allowing efficient carbon source utilization. In the soil bacterium Acinetobacter baylyi, this mechanism has been shown to apply to the aromatic degradative pathways for the substrates protocatechuate, p-hydroxybenzoate and vanillate. In this investigation, transcriptional fusions with the gene for luciferase in the gene clusters for the de...

Cell-free homogenates prepared from broad-bean seeds and yeast cells are capable of synthesizing 4-carboxy-2-polyprenylphenols from p-hydroxybenzoate and either isopentenyl pyrophosphate or protein-bound polyprenyl pyrophosphates (produced by incubating a Micrococcus lysodeikticus extract with isopentenyl pyrophosphate). The mitochondria contained all the polyprenyl pyrophosphate-p-hydroxybenzo...