13925-07-0Relevant articles and documents
Comparison of pyrazines formation in methionine/glucose and corresponding Amadori rearrangement product model
Cui, Heping,Deng, Shibin,Hayat, Khizar,Ho, Chi-Tang,Zhai, Yun,Zhang, Qiang,Zhang, Xiaoming
, (2022/03/07)
The generation of pyrazines in a binary methionine/glucose (Met/Glc) mixture and corresponding methionine/glucose-derived Amadori rearrangement product (MG-ARP) was studied. Quantitative analyses of pyrazines and methional revealed that MG-ARP generated more methional compared to Met/Glc, whereas lower content and fewer species of pyrazines were observed in the MG-ARP model. Comparing the availability of α-dicarbonyl compounds generated from the Met/Glc model, methylglyoxal (MGO) was a considerably effective α-dicarbonyl compound for the formation of pyrazines during MG-ARP degradation, but glyoxal (GO) produced from MG-ARP did not effectively participate in the corresponding formation of pyrazines due to the asynchrony on the formation of GO and recovered Met. Diacetyl (DA) content was not high enough to form corresponding pyrazines in the MG-ARP model. The insufficient interaction of precursors and rapid drops in pH limited the formation of pyrazines during MG-ARP degradation. Increasing reaction temperature could reduce the negative inhibitory effect by promoting the content of precursors.
Alkylations and hydroxymethylations of pyrazines via green minisci-type reactions
Bohman, Bjorn,Berntsson, Benjamin,Dixon, Ruby C. M.,Stewart, Craig D.,Barrow, Russell A.
supporting information, p. 2787 - 2789 (2014/06/23)
A new general methodology utilizing Minisci-type chemistry has been developed that cleanly and efficiently prepares alkyl- and (hydroxymethyl) pyrazines. The new methods eliminate toxic catalysts and halogenated solvents, providing a greatly improved route to these natural products which are prevalent in many natural systems as bacterial volatiles, plant volatiles, and insect pheromones.
Pyrazine biosynthesis in corynebacterium glutamicum
Dickschat, Jeroen S.,Wickel, Susanne,Bolten, Christoph J.,Nawrath, Thorben,Schulz, Stefan,Wittmann, Christoph
supporting information; experimental part, p. 2687 - 2695 (2010/08/07)
The volatile compounds released by Corynebacterium glutamicum were collected by use of the CLSA technique (closed-loop stripping apparatus) and analysed by GC-MS. The headspace extracts contained several acyloins and pyrazines that were identified by their synthesis or comparison to commercial standards. Feeding experiments with [2H7]acetoin resulted in the incorporation of labelling into trimethylpyrazine and tetramethylpyrazine. Several deletion mutants targeting genes of the primary metabolism, were constructed to elucidate the biosynthetic pathway to pyrazines in detail. A deletion mutant of the ketol-acid reductoisomerase was not able to convert the acetoin precursor (S)2-acetolactate into the pathway intermediate (R)-2,3-dihydroxy-3-methylbutanoate to the branched amino acids. This mutant requires valine, leucine, and isoleucine for growth and produces significantly higher amounts and more different compounds of the acyloin and pyrazine classes. Gene deletion of the acetolactate synthase (AS) resulted in a mutant that is not able to convert pyruvate into (5)-2-acetolactate. This mutant also requires branched amino acids and produces only very small amounts of pyrazines likely from valine via the valine biosynthetic pathway operating in reverse order. A ΔASΔKR double mutant was constructed that does not produce any pyrazines at all. These results open up a detailed biosynthetic model for the formation of alkylated pyrazines via acyloins.
