The constitution of Chlamydocin – a metabolite of Diheterospora chlamydosporia with pronounced cytostatic activity – is proposed on the basis of chemical reactions and physical data. The synthesis of a derivative of a new amino acid is described. The biological activities of this compound and of derivatives of Chlamydocin are discussed.

Isolierung und Strukturaufklärung von Chlamydocin

The Clarke-Carbon clone bank of hybrid plasmid Escherichia coli DNA has been screened for plasmids able to complement an E. coli strain deficient for the production of beta-cystathionase. Clone 4-14 had the ability to complement a deletion mutation at this locus and expressed higher levels of beta-cystathionase than the wild-type strain. The transfer of the plasmid carried by this clone to a strain that constitutively expresses all the enzymes of the methionine biosynthetic pathway results in 100-fold overproduction of beta-cystathionase as compared to wild-type levels. With use of this strain, an efficient three-step purification scheme is described that gives 90% pure enzyme in 54% yield with a specific activity of 215 IU/mg. This enzyme is characterized as to molecular weight (280 000), number of subunits (six), pyridoxal phosphate binding (5.7 mol of pyridoxal phosphate bound/mol of protein, Km of 0.005 mM), amino acid composition, substrate specificity, and kinetic properties.

Cloning, purification, and characterization of beta-cystathionase from Escherichia coli.

A series of derivatives of the phenylpyrrole fungicide fenpiclonil was synthesized in which a carboxyl group was present at various sites of this non-phloem-mobile molecule. Using the Kleier model, all these acidic analogues were predicted to be moderately phloem-mobile, especially the N-substituted derivatives. One of these latter molecules, N-carboxymethyl-3-cyano-4-(2,3-dichlorophenyl)pyrrole, exhibited some fungicidal activity on the pathogenic fungus Eutypa lata, and was then tested as a phloem-mobile pesticide in the Ricinus system. The compound was indeed mobile in the sieve tubes and was not degraded to fenpiclonil in the phloem sap under our experimental conditions. Its concentration in the sap was closely correlated to the percentage of the undissociated form of the molecule in the external medium, and was similar under acidic conditions (external pH 4.6-5.0) to that of the herbicide glyphosate.

/pdf/synthesis-and-phloem-mobility-of-acidic-derivatives-of-the-2vrz36fbq9.pdf

Synthesis and phloem mobility of acidic derivatives of the fungicide fenpiclonil

The title compound, an analogue of [Leu5]-enkephalin with L-o-carboranylalanine replacing L-phenylalanine in position 4, was prepared by fragment condensation. The analogue has a 3-fold higher affinity for rat brain opiate receptors in the [3H]naloxone competition assay than natural [Leu5]-enkephalin. Like [Leu5]-enkephalin and Na-acetyl-[Leu5]-enkephalin, the N-terminal tripeptide fragment, H · Tyr-Gly-Gly · OH, had no melanotropic activity in the Rana pipiens frog skin assay.



A convenient, direct synthesis of methyl t-butoxycarbonyl-L-propargylglycinate is described, and the 13C-NMR. spectra of L-o-carboranylalanine recorded. The procedure was extended to the preparation of BOC · Car-Leu · OMe from BOC · Pra-Leu · OMe. A number of new propargylglycine derivatives are reported.

The Synthesis of [4‐Carboranylalanine, 5‐Leucine]‐Enkephalin (Including an Improved Preparation of t‐Butoxycarbonyl‐L‐o‐carboranylalnine, New Derivatives of L‐Propargylglycine, and a Note on Melanotropic and Opiate Receptor Binding Characteristics)

Irreversible inactivation of aspartate aminotransferases during transamination with L-propargylglycine.

The Syntheses and Microbiological Properties of Acetylenic Amino Acids. Propargylglycine and 2-Amino-3-methyl-4-pentynoic Acid1

Sodium Hydride as a Condensing Agent with Acylaminomalonates in the Synthesis of Amino Acids1,2

Shapira, Jacob (Department of Chemistry, Florida State University, Tallahassee) and Karl Dittmer. Unsaturated amino acids. V. Microbiological properties of some halogenated olefinic amino acids. J. Bacteriol. 82:640–647. 1961.—It has been shown previously that several amino acid analogues containing unsaturated linkages were inhibitors of the growth of Escherichia coli and Saccharomyces cerevisiae. This paper reports the results obtained when a series of unsaturated halogen-containing amino acids was examined. The cis isomer of ω-chloroallylglycine showed the greatest toxicity yet found in this series of unsaturated amino acids toward E. coli, whereas the trans-isomer was usually far less toxic. The major effect of cis-ω-chloroallylglycine in E. coli appeared to be to extend the lag phase before the normal rate of growth began. A wide variety of amino acids was capable of partially or completely preventing the toxicity of low levels of these compounds. At higher levels, relatively few amino acids (primarily valine, leucine, and glutamic acid) were effective. In E. coli, cis-ω-chloroallylglycine showed an unusual [Formula: see text] relationship with both glutamic acid and valine over a wide range in concentration.

UNSATURATED AMINO ACIDS V. Microbiological Properties of Some Halogenated Olefinic Amino Acids

Unsaturated Amino Acids. IV. Synthesis of Halogen Substituted Allyglycines1,2

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The Syntheses and Microbiological Properties of Acetylenic Amino Acids. Propargylglycine and 2-Amino-3-methyl-4-pentynoic Acid1

Sodium Hydride as a Condensing Agent with Acylaminomalonates in the Synthesis of Amino Acids1,2

UNSATURATED AMINO ACIDS V. Microbiological Properties of Some Halogenated Olefinic Amino Acids

Unsaturated Amino Acids. IV. Synthesis of Halogen Substituted Allyglycines1,2