Yang Mo Goo

A New Method for the Preparation of β-Hydroxy Nitriles: Transformation of 3-Bromo-2-isoxazolines to β-Hydroxy Nitriles by Treatment of Alkanethiolates

Abstract 3-Bromo-2-isoxazolines are transformed to β-hydroxy nitriles in good yields by treatment with alkanethiolates under a very mild condition.

Hydrolysis of various nitrile compounds to the amides by catalysis of 2-mercaptoethanol in a phosphate buffer

Abstract α-Aminonitriles, 4-nitrobenzonitrile and 3,5-dinitrobenzonitrile were hydrolyzed exclusively to amides efficiently when they were stirred with 2-mercaptoethanol in a phosphate buffer (pH 7.0), 50 mM).

Kanamycin acetyltransferase gene from kanamycin-producingStreptomyces kanamyceticus IFO 13414

A kanamycin producer,Streptomyces kanamyceticus IFO 13414 is highly resistant to kanamycin. Cloning of the kanamycin resistance genes inS. lividans 1326 with pIJ702 gave several kanamycin resistant transformants. Two transformants,S. lividans SNUS 90041 andS. lividans SNUS 91051 showed similar resistance patterns to various aminoglycoside antibiotics. Gene mapping experiments revealed that plasmids pSJ5030 and pSJ2131 isolated from the transformants have common resistant gene fragments. Subcloning of pSJ5030 gave a 1.8 Kb gene fragment which showed resistance to kanamycin. Cell free extracts ofS. lividans SNUS 90041,S. lividans SNUS 91051 and subclone aS. lividans SNUS 91064 showed kanamycin acetyltransferase activity. The detailed gene map is included.

A new streptothricin family antibiotic producingStreptomyces spp. SNUS 8810-111; Characterization of the producing organisms, fermentation, isolation, and structure elucidation of antibioitics

A new streptothricin family antibiotic producingStreptomyces spp. SNUS 8810-111 was isolated from a soil sample. Study of its morphological and physiological characters indicated that the antibiotic producing organism was aStreptomyces spp. Taxonomical studies suggested that the organism might belong to the genusStreptomyces gougeroti. The organism produced antibiotics most in calcium carbonate-tryptic soy broth. The active principles were recovered from the broth with a cation exchange resin and eluted from the resin with HCl. Cellulose column chromatography gave two active principles.1H-1H Homo-COSY study on the first compound revealed four structural components. Total hydrolysis of the antibiotic with HCl allowed isolation of β-lysine. From these data the antibiotic was found to be streptothricin D. The other compound showed one additional signal in the1H NMR and the13C NMR spectra. The signal was from a methyl group attached to a nitrogen atom. Comparison of the NMR signals with those of streptothricin D suggested that the compound wasN-methyl-streptothricin D which was a new compound in the family of streptothricin antibiotics.

Microbiological oxidation of isophorone to 4-hydroxyisophorone and chemical transformation of 4-hydroxyisophorone to 2,3,5-trimethyl-p-benzoquinone

Oxidation of isophorone by various fungi was examined.Aspergillus niger oxidized isophorone to 4-hydroxyisophorone, 3-hydroxymethyl-5,5-dimethyl-2-cyclohexen-1-one and 5-hydroxymethyl-3,5-dimethyl-2-cyclohexen-1-one. 4-Oxoisophorone obtained by chromic acid oxidation of 4-hydroxyisophorone was transformed to 2,3,5-trimethyl-p-benzoquinone by acid treatment.

Microbial aspartase and its activity on deamination of L-aspartyl-L-phenylalanine methyl ester

Examination of many microorganisms and soil isolates for the activity of aspartase proved thatR. rubra, G. suboxydans, A. versicolor, P. purpurogenum, E. coli, Ps. aeruginosa, A. gigantus, A. unguis, A. parasiticus and a soil isolate(S-90) had high activity of aspartase. Comparision of the activity of the aspartase by cell free extracts of these micro-organisms with the activity of the enzyme catalyzing the deamination of aspartame by the same cell free extracts showed similar kinetic characteristics. The aspartase existing in the cell free extracts seemed to catalyze the deamination of aspartame, too.

Identification of actinomycins by high performance liquid chromatography and fast atom bombardment mass spectrometry

An actinomycin complex isolated from culture broth of a soil microorganism, SNUS 9305-011 has been examined by High performance liquid chromatography (HPLC). From the analysis of the fractions obtained by column chromatography of the ethyl acetate extract, three actinomycin components are confirmed. The HPLC analysis is carried out with a CN-bonded nucleosil column. Comparison of the retention times of the components with those of actinomycin D, C complex, Xoβ, and V suggests that they are different actinomycins. FAB mass spectra of the components also shows different molecular ions from those of standards and other reported actinomycins. The present work has demonstrated that actinomycin components can be separated by a CN-bonded HPLC column, and that comparison of their HPLC chromatograms with authentic samples and information on their molecular ions can be successfully employed for identification of actinomycins.

Effects of natural selection, mutagenesis, and protoplast formation and cell wall regeneration on the production of aminoglycoside antibitics

High producers or blocked mutants of aminoglycoside antibiotic-producingStreptomyces spp. were selected by application of an agar plug method and by culturing individual colonies in broth. The productivities of aminoglycoside antibiotic producing organisms were increased by selection of a high producer from colonies obtained by spreading spores of wild strain, or survived from treatment of a mutagen or from the colonies regenerated from protoplast-formation and cell-wall regeneration. Some mutagen treated colonies lost the ability to produce antibiotics (5–8%). Some A-factor negative and deostreptamine or streptidine negative mutants were obtained by N-methyl-N’-nitro-N-nitrosomethylguanidine (MNNG) treatment. Many of the survivors from the MNNG treatment lost the ability to produce antibiotics. Major colonies produced less amount of antibiotics; only few survived colonies produced more antibiotics than the parent. Resistance ofStreptomyces spp. against the antibiotics produced by itself was also markedly affected by mutagen treatment.

Synthetic studies on carbapenem and penem antibiotics(VI) improved synthesis of (3S,4S)-4-acetoxy-3-phenylacetamido-azetidin-2-one

Penicillin G potassium salt was transformed in high yield to 4-acetoxy-3-phenylacetaminoazetidinone by treatment of mercury acetate, ozonolysis and methanol in sequence.

Bifunctional group participated nitrile group hydrolyzing enzyme model systems: Hydrolysis of the nitrile group of α-aminophenylacetonitrile to phenylglycineamide and phenylglycine by various thiol compounds

Abstract2-Mercaptoethanol, thioglycolic acid, glutathione, 3-mercapto-1,2-propanediol and 3-mercapto-2-butanol showed catalytic activities on the hydrolysis of α-aminophenylacetonitrile to phenylglycineamide at the rate of 12.19×10−2, 8.03×10−2, 6.83×10−2, 8.60×10−2 and 6.04×10−2 mM min−1, respectively. The hydrolysis rate was faster in buffer than in water. The hydrolysis of the nitrile compound to phenylglycine was limited.