Irving Putter

Avermectins, New Family of Potent Anthelmintic Agents: Isolation and Chromatographic Properties

The avermectins, a family of new anthelmintic agents, were isolated from the mycelia of Streptomyces avermitilis. Four closely related major components and four homologous minor components were separated from the complex. Solvent extraction, solvent partition, and adsorption methods were used to isolate and purify the complex; novel partition chromatography systems using Sephadex LH-20 were used to separate the components. A reverse-phase high-pressure liquid chromatography assay for the quantitative determination of all components was used extensively to monitor the purification methods.

Cephamycins, a New Family of β-Lactam Antibiotics II. Isolation and Chemical Characterization

Cephamycins A and B were isolated from the same fermentation broth of various actinomycetes by adsorption and ion-exchange methods. The antibiotics were separated from each other by column chromatography on a dextran-based ion-exchange resin. Cephamycin C was isolated from a different fermentation broth by ion-exchange and gel-filtration methods. The chemical characteristics of these new antibiotics were determined.

Gas-liquid chromatography and mass spectrometry of deuterium-containing amino acids as their trimethylsilyl derivatives

Abstract The gas-liquid chromatography and mass spectrometry of specially labeled deuterium-containing amino acids as their trimethylsilyl derivatives has been investigated. In many cases the retention time of the deuterated compound was measurably shorter than that of its protium analog. The small retention time differences, to a first approximation, were proportional to the number of deuterium atoms. Under our experimental conditions separation of mixtures (bifurcated peak) was observed within only two pairs of compounds—leucine and leucine-D 10 , and isoleucine and isoleucine-D 10 . Fractionation of the protium and deuterium forms within a single gas-liquid chromatography peak has been demonstrated by combined gas-liquid chromatography —multiscan mass spectrometry. Comaparison of the mass spectra of normal amino acid trimethylsilyl derivatives and their deutrium-containing analogs has facilitated the elucidation of the mass spectral fragmentation patters observed for these compounds.

The isolation of deuterated amino acids

Abstract The preparative separation of a deuterated protein hydrolysate is described. The deuterium-exchange properties of the individual amino acids are discussed and related to applications of proton magnetic resonance.

Applications of nuclear magnetic resonance in biochemistry: An analysis of the aromatic region of the proton magnetic resonance spectrum of staphylococcal nuclease

SummaryGeneral procedures for the simplification and analysis of nuclear magnetic resonance spectra of proteins are presented. These are illustrated with current results with the enzyme staphylococcal nuclease which have permitted a partial analysis of the aromatic region of its proton nuclear magnetic resonance spectrum.ZusammenfassungAllgemeine Verfahren zur Auswertung und Vereinfachung der kernmagnetischen Resonanzspektren von Proteinen werden diskutiert und an Hand neuer Ergebnisse mit dem Enzym Staphylococcus-Nuclease demonstriert. Bei diesem Enzym gelang eine Teilanalyse des aromatischen Bereichs des KMR-Spektrums.