A series of 5-(3'-oxo-6'-(substituted aryl)-2',3',4',5'-tetrahydropyridazin-2'-ylmethyl )-2-substituted 1,3,4-oxadiazole has been synthesized. Appropriate aromatic hydrocarbon reacts with succinic anhydride in the presence of AICl3 to yield beta-aroyl propionic acid (1a). The corresponding acid is cyclized with hydrazine hydrate to give 6-(substituted aryl)-2,3,4,5-tetrahydro-3-pyridazinone (1b...

Human placental estradiol-17P dehydrogenase is rapidly inactivated upon treatment with 3-bromoacetoxyestrone. Pseudo-first order kinetic data are obtained and inactivation is accompanied by incorporation of 1 mol of 3-acetoxyestrone/mol of subunit (M, = 34,000). Treatment of the inactivated enzyme with (4S)[4-2H]DPNH results in the formation of covalently bound [17cu-2H]estradiol-17/3, which ca...

Nemere, Ilka, Rahul Ray, and William McManus. Immunochemical studies on the putative plasmalemmal receptor for 1,25(OH)2D3. I. Chick intestine. Am J Physiol Endocrinol Metab 278: E1104–E1114, 2000.—Antisera were raised against the NH2-terminus of the putative basal lateral membrane (BLM) receptor for 1,25-dihydroxyvitamin D3 [1,25(OH)2D3; BLM-VDR]. In Western analyses of BLM proteins, antibody ...

The mammalian-type cytochrome c of the basidiomycete Ustilago sphaerogena contains in a single polypeptide chain of 107 residues, two histidine residues located at positions 18 and 33, and one methionine residue situated at position 80 (Bitar et al., 1972). The reaction of Ustilago ferricytochrome c with bromoacetate at neutral pH resulted in the modification of histidine-33, but not of histidi...

The reaction of iodoacetic acid with ribonuclease has been studied recently by Gundlach et al. (1). Inactivation of the enzyme occurred over a wide range of pH. The authors concluded that at acid pH the reaction involved solely methionyl residues, that at pH 5.5 a histidyl residue was the principal site of attack, and that at alkaline pH values significant reaction at lysyl residues occurred. O...

Two strategies are applied to mimic the ampholytic nature of the surfaces of half-generation PAMAM dendrimers and yet retain the very narrow dispersity inherent of triazine dendrimers. Both strategies start with a monodisperse, single-chemical entity, generation two triazine dendrimer presenting twelve surface amines that is available at the kilogram scale. The first method relies on reaction w...

To further characterize the active site of human placental oestradiol17/3-dehydrogenase (EC 1.1.1.62), we have synthesized 4-bromoacetamidoestrone methyl ether. Starting with estrone, synthetic steps involved nitration, isolation of the I-nitro derivative with subsequent methylation, selective reduction of the nitro group, and coupling of the resulting 4-amino group with bromoacetic acid. The a...

The interactions of horse spleen ferritin and its derivative apoferritin with H+ ions were studied by potentiometric and spectrophotometric titration; to aid in data analysis, heats of ionization over a limited pH range and amide content were also determined. Per apoferritin subunit, all tyrosine and cysteine side chains, two of the nine lysine side chains and at least three of the six histidin...

Cleavage of rabbit muscle aldolase by cyanogen bromide results in the formation of four fragments of different size [1]. Study of the primary structure of the enzyme has been based on the examination of these fragments [1, 2]. Because of the insolubility and associated problems due to the relatively large size of the fragments Lai [1], as well as Anderson et al. [3], used pyridine-acetic acid b...