Sulfhydryl groups of cyclic AMP-dependent histone kinase from pig brain]

A preparative method of isolation of the histone kinase regulatory subunit has been developed. The total number of cysteine residues in the enzyme (13 residues) and in each of its subunits (3 residues in the catalytic subunit and 10 residues in the regulatory one), has been determined. Two disulfide bridges have been found in the regulatory subunits. The relative availability of the sulfhydryl groups with respect to different modifying agents has been studied. It has been demonstrated that SH-groups blocking does not change essentially the enzyme activity.     

Aroma-Forming Substances from a Culture of the Mold Fungus Penicillium roquefortiGrown on Curd

Production of aroma-forming substances by Penicillium roquefortistrains No. 31 and No. 541-A grown on curd was studied. The data showed that strain No. 541-A is the most promising producer of cheese flavor. The flavor acquired a soily scent after more than 5 days cultivation, which may hamper the use of these cultures (particularly, No. 31) in the food industry.     

Structural studies of the O-specific side chain of the lipopolysaccharide from Escherichia coli O:7

The structure of the O-specific side-chain of the lipopolysaccharide from Escherichia coli O:7 has been investigated, using n.m.r. spectroscopy, methylation analysis, partial hydrolysis, and Smith degradation as the principal methods. It is concluded that the polysaccharide is constructed of repeating pentasaccharide units having the structure (formula; see text) where D-QuipNAc stands for 4-acetamido-4,6-dideoxy-D-glucopyranose. The 13C-n.m.r. spectrum of the polysaccharide has been interpreted completely.     

Computer analysis of polysaccharides with linear repetitive link from 13C-NMR data

The possibility of computerised analysis of primary structures of polysaccharides on the basis of 13C NMR data and average values of alpha- and beta-effects of glycosidation was evaluated. Theoretical 13C NMR spectra for all possible structures of some linear polysaccharides were calculated by using additive scheme of glycosidation effects. In each case it was found that the structure characterised by the least sum of squared deviations of chemical shifts for the signals in the calculated and experimental spectra corresponds to the sequence and modes of linkages between monosaccharide residues in polysaccharides determined by an independent way.     

Preparation and analysis of mutants of rhizospheric pseudomonads, resistant to toxic analogs of tryptophan and phenylalanine]

The absence of plasmids in strains of fluorescent pseudomonads characterized by high level of synthesis of phytohormone indole-3-acetic acid (IAA) as well as invariability of this feature in plasmid and non-plasmid variants of strain BSP8 suggests chromosomal control of IAA synthesis by the rhizosphere bacteria tested. Using toxic analogues of aromatic amino acids -5-fluorine-tryptophan and 5-methyl-tryptophan variants were obtained which synthesized and secreted only anthranilic acid. Mutants with resistance to p-fluorine-phenylalanine and capable of secreting tryptophan and/or phenylalanine were found. Testing of the secreting variants failed to reveal any differences between the levels of IAA biosynthesis in comparison with the wild-type strains.     

Antigenic bacterial polysaccharides. 23. The structure of the O-specific polysaccharide chain of Salmonella arizonae 059 lipopolysaccharide

The O-specific polysaccharide of Salmonella arizonae O59 (Arizona 19) is composed of D-galactose, N-acetyl-D-glucosamine, and N-acetyl-L-fucosamine (FucNAc, 2-acetamido-2,6-dideoxy-L-galactose) in the ratio 1:1:1. The computerized calculation of the 13C NMR spectrum of the polysaccharide, based on the monosaccharide composition, spectra of the free monosaccharides and glycosydation effects, together with the chemical analysis (methylation and Smith degradation) showed that the polysaccharide is built up of trisaccharide repeating units of the following structure: ----3)-alpha-L-FucNAcp(1----3)-beta-D-GlcNAcp-(1----2)-beta- D-Galp-1(----. The molecular basis of serological interrelations between S. arizonae O59 and Pseudomonas aeruginosa O7 (Lányi) is discussed.     

Mechanism of action of cAMP-dependent protein kinase. III. Probable role of an enzyme carboxyl group

By the method of chemical modification the active site of cAMP-dependent pig brain protein kinase was shown to contain a carboxyl group. The kinetic parameters of irreversible inhibition of the enzyme by water-soluble carbodiimide in the presence of ethyl ester of glycine were determined. The ionized carboxyl group-containing amino acid residue found is evidently localized in the immediate proximity to the reaction center. The comparison of the reaction rates of phosphate transfer from the intermediate phosphoform of the enzyme under native and denatured conditions suggests that this residue acts as the general base catalyst of this process.     

The nuclear Overhauser effect and structural factors determining the conformation of disaccharides

Conformational analysis of 1.2-, 1.3- and 1.4-linked disaccharides built up of aldohexapyranose residues was performed on the basis of interresidue nuclear Overhauser effects in 1H-NMR spectra and theoretical calculation using atom-atom potential functions. It was shown that the preferred conformation of the disaccharides is determined by the following factors: absolute configurations of monosaccharide residues, configuration and position of the glycosidic linkage, orientation of protons at the aglycon carbon atom involved in the glycosidic linkage and at the adjacent carbons atoms.