Combination Of High-resolution Mass Spectrometry Research Articles

Novel pyrazine metabolites found in polymyxin biosynthesis by Paenibacillus polymyxa

A complex mixture of methyl-branched alkyl-substituted pyrazines was found in the growth medium of the polymyxin-producing bacterium Paenibacillus polymyxa, and of these, seven are new natural compounds. A total of 19 pyrazine metabolites were identified. The dominant metabolite was 2,5-diisopropylpyrazine as identified using a combination of high-resolution mass spectrometry, 1H- and 13C-nuclear magnetic resonance, gas chromatography-mass spectrometry as well as co-elution with an authentic standard. Its biosynthesis was correlated with growth and production was strongly stimulated by valine supplementation. The other pyrazine metabolites, all related pyrazines with either one, two or three alkyl substituents, were identified by means of their mass spectral data and/or co-elution with authentic standards.

Identification of yeast proteins by mass spectrometry

Publisher Summary This chapter discusses the principles and practical protocols involved in the mass spectrometric identification of yeast proteins. Mass spectrometry has improved the toolbox of biochemical strategies by providing rapid and high throughput identification of proteins in yeast. The wide variety of mass spectrometers available commercially can be distinguished by the way ions are produced (ion sources) and the way they are separated (mass analyzers). The most commonly used ion sources for biological applications are matrix-assisted laser desorption and ionization (MALDI) and electrospray (ES) ionization. Both of them are known as “soft ionization methods,” permitting the transfer of the biological compound into the gas phase of the mass analyzer without decomposition. A rapid and sensitive analysis of yeast protein complexes or interacting partners can be achieved by liquid chromatography–mass spectrometry (LC–MS) approaches. The combination of high-resolution mass spectrometry, data-dependent software, and nanoflow liquid chromatography allows the creation of a robust system for the characterization of complex mixtures. The chapter discusses the methods for protein identification.

Future Aspects of Psychoneuroimmunology – Lymphocyte Peptides Reflecting Psychiatric Disorders Studied by Mass Spectrometry

We have investigated whether cytoplasmatic and nuclear extracts of human peripheral blood lymphocytes contain arginine vasopressin (AVP), of importance for memory functions, in samples from healthy controls and patients diagnosed as depressed. It is the first time as AVP, AVP-fragments and chemically modified AVP-forms have been demonstrated in lymphocyte/nuclear extracts. This was performed by an HPLC-purification step, followed by a second immunoprecipitation step before identification by mass spectrometry. We are developing new methods using a combination of high-resolution mass spectrometry and separation techniques such as capillary electrophoresis and nano liquid chromatography. We have named this methodological approach when studying endogenous peptides -Peptidomics.

Mass Spectrometric Analysis of Oil Produced from Catalytic Hydrogenation of Yubarishinko Coal

Yubarishinko coal was hydrogenated with Adkins catalyst, and the prod-uct was extracted with hexane in a soxhiet extractor. The oil was separated into neutral oil, acidic oil and basic oil. The neutral oil was further fractionated into saturated hydro-carbons (Fr-P), monoaromatic (Fr-M), diaromatic (Fr-D), three or more aromatic rings (Fr-T) and polyaromatic-polar hydrocarbons (Fr-PP) by means of dual-packed liquid chromatography developed according to API-project 60 method.Both acidic and basic oil were subjected to analysis by combined high resolution mass spectrometry and low voltage low resolution mass spectrometry. The acidic oil was mainly composed of mono aromatic ring hydrocarbons with alkyl side chains of about two carbon atoms and a hydroxyl group.The major compound types of the basic oil were the mass Z series rom-11N to-21N compounds with three or four alkyl carbons. GC/MS analysis of Fr-P indicated that n-paraffins were major constituents and a little mono cyclic saturated hydrocarbons with a straight chain existed. For aromatic fraction (Fr-M, Fr-D and Fr-T), compounds in each mass Z series were eluted from-8 series to-32 series nearly in order. Mass Z series, -12, -14, and -16, were major constituents. Fr-PP included too many com-pounds to be evaluated by mass spectrometry.