Ten synthetic dihydropyridine analogues were investigated for their ability to reverse drug resistance in a multidrug-resistant human carcinoma cell line, KB-Cl. Four dihydropyridine analogues completely reversed the resistance, three lowered the resistance, and three had little effect. The radioactive photoactive dihydropyridine calcium channel blocker, [3H]azidopine, photolabels P-glycoprotei...

The polyamines spermidine and spermine and their diamine precursor putrescine are essential for mammalian cell growth and viability, and strategies are sought for reducing polyamine levels in order to inhibit cancer growth. Several structural analogues of the polyamines have been found to decrease natural polyamine levels and inhibit cell growth, probably by stimulating normal feedback mechanis...

It has been previously shown (l-3) that the nicotinamide moiety of diphosphopyridine nucleotide can be replaced by other pyridine bases without the loss of the coenzyme function. The observation that both the 3-acetylpyridine and pyridine-3aldehyde analogues of diphosphopyridine nucleotide function as coensymes with various dehydrogenases (3) indicated that the amide group on DPN was not essent...

Eight- and four-membered analogues of N-butyldeoxynojirimycin (NB-DNJ), a reversible male contraceptive in mice, were prepared and tested. A chiral pool approach was used for the synthesis of the target compounds. Key steps for the synthesis of the eight-membered analogues involve ring-closing metathesis and Sharpless asymmetric dihydroxylation and for the four-membered analogues Sharpless epox...

Incorporation of Trp (tryptophan) analogues into a protein may facilitate its structural analysis by spectroscopic techniques. Development of a biological system for the biosynthetic incorpor-ation of such analogues into proteins is of considerable importance. The Gram-negative Escherichia coli is the only prokaryotic expression host regularly used for the incorporation of Trp analogues into re...

Numerous biophysical tools based on fluorescence have been developed to advance the understanding of RNA–nucleic acid, RNA–protein, and RNA–small molecule inter actions. In this regard, fluorescent ribonucleoside analogues that are sensitive to their local environment provide sensitive probes for investigating RNA structure, dynamics, and recognition. Most of these analogues closely resemble th...

The effect of GTP analogues on catecholamine secretion and [3H]arachidonic acid release from digitonin-permeabilized adrenal chromaffin cells was examined. Several GTP analogues stimulated Ca2(+)-independent exocytosis, with the order of efficacy being XTP greater than ITP greater than guanosine 5'-[beta gamma-imido]triphosphate (p[NH]ppG) greater than guanosine 5'-[gamma-thio]triphosphate (GTP...

Chemically modified bases are frequently used to stabilize nucleic acids, to study the driving forces for nucleic acid structure formation and to tune DNA and RNA hybridization conditions. In particular, fluorobenzene and fluorobenzimidazole base analogues can act as universal bases able to pair with any natural base and to stabilize RNA duplex formation. Although these base analogues are compa...

In this paper we determined the pharmacological profiles of novel ketamine and phencyclidine analogues currently used as 'designer drugs' and compared them to the parent substances via the resources of the National Institute of Mental Health Psychoactive Drug Screening Program. The ketamine analogues methoxetamine ((RS)-2-(ethylamino)-2-(3-methoxyphenyl)cyclohexanone) and 3-MeO-PCE (N-ethyl-1-(...

The effect of introducing D-amino acid residues in an hexapeptide was examined both at the antigenic and immunogenic levels. A series of D-analogues of the model peptide of sequence IRGERA corresponding to the COOH-terminal residues 130-135 of histone H3 were produced. Four analogues contained a single change of an L-residue by the corresponding enantiomer, one peptide contained two D-residues ...