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Distribution of nitrogen compounds in important sections of sugar beets

Bąk P., Antczak-Chrobot A., Wojtczak M.

Biotechnology and Food Science

2016

Vol. 80, nr 1

53--61

In literature the beet is often described as consisting of the following technologically important sections: crown, root and tail. The aim of the study was to determine the distribution of nitrogen compounds in the technologically important beet sections of untopped sugar beets with particular emphasis on the content of nitrate and nitrite. The Finezja sugar beet variety had been collected from the clamps in one of the Polish sugar factories in October during 2013/2014 campaign. The untopped sugar beets were divided into three sections: crown, root and tail. The content of total amount of nitrogen, proteinaceous nitrogen, α-amino nitrogen, the sum of the amide and ammonia nitrogen, nitrates and nitrite in these sections were determined. Although the crown of the sugar beet represented only 14.7% of it mass, this section contained on average 30% of the total quantity of α-amino acids as well as amide and ammonia nitrogen.This section contained approximately 77% of the total quantity of nitrate and 88% of nitrite. Untopped sugar beets would introduce much higher amounts of nitrogen compounds in comparison to topped raw material.

Synthesis and application of new chiral variants of Marfey's reagent for liquid chromatographic separation of the enantiomers of α -amino acids

Bhushan R., Kumar V.

Acta Chromatographica

2008

Vol. 20, no. 3

329-347

Two new structural variants of Marfey's reagent (1-fluoro-2,4-dinitrophenyl-5-L -alaninamide, FDNP-L -Ala-NH 2 ) were synthesized by nucleophilic substitution of one fluorine atom in 1,5-difluoro-2,4-dinitrobenzene (DFDNB) by L -methioninamide or D -phenylglycinamide. The new variants FDNP-L -Met-NH 2 and FDNP-D -Phg-NH 2 were characterized and used for derivatization of twenty-six α-amino acids. The resulting diastereomeric derivatives were separated on a reversed-phase C 18 HPLC column using a linear gradient of acetonitrile and aqueous trifluoroacetic acid (TFA) and the results were compared with those obtained by use of Marfey's reagent. To determine and establish the efficiency of both the new variants, separation results were compared for diastereomers of five representative amino acids (Ala, Phe, Ser, Asp, and Asn) prepared with MR, FDNP-L-Phe-NH 2 , FDNP-L -Val-NH 2 , FDNP-L -Leu-NH 2 , and FDNP-L -Pro-NH 2 , experiments being performed under identical conditions. Both the new chiral reagents enabled better separation of the diastereomers than Marfey's reagent for most of the amino acids. The reagent FDNP-D -Phg-NH 2 enabled excellent separation for serine and asparagine whereas other reagents failed or provided poor results.