Evaluation of the Site Specific Protein Glycation and Antioxidant Capacity of Rare Sugar-Protein/Peptide Conjugates
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- 作者：Yuanxia Sun ; Shigeru Hayakawa ; Masahiro Ogawa ; and Ken Izumori
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2005
- 出版时间：December 28, 2005
- 年：2005
- 卷：53
- 期：26
- 页码：10205 - 10212
- 全文大小：182K
- 年卷期：v.53,no.26(December 28, 2005)
- ISSN：1520-5118
文摘
Protein-sugar conjugates generated in nonenzymatic glycation of 
-lactalbumin (LA) with rare sugars[D-allose (All) and D-psicose (Psi)] and alimentary sugars as controls [D-glucose (Glc) and D-fructose(Fru)] were qualitatively determined by matrix-assisted laser desorption/ionization time-of-flight massspectrometry (MALDI-TOF-MS). Mass spectra revealed that the extent of glycation at lysine residueson LA with D-aldose molecules was very much higher than that of glycation with D-ketose molecules.To identify the specific site of glycation, the peptide mapping was established from protease V8digestion, using a combination of computational cutting of proteins and MALDI-TOF-MS. As comparedto peptide mapping, three and seven glycation sites were located in the primary structure of LA-ketose and LA-aldose conjugates, respectively. On the other hand, the antioxidant activities ofprotein-sugar conjugates and their peptic hydrolysates were investigated by 1,1-diphenyl-2-picrylhydrazyl radical scavenging method. The antioxidant activities of proteins/peptides glycated withrare sugars were significantly higher than those modified with the control sugars. The results indicatedthat the glycation degree and position were not markedly different between rare sugar andcorresponding control sugar, but the antioxidant properties of protein and its hydrolysate weresignificantly enhanced by modifying with rare sugar.Keywords: -Lactalbumin; rare sugar; glycation; antioxidant activity; peptide-mapping; MALDI-TOF-MS
-lactalbumin (LA) with rare sugars[D-allose (All) and D-psicose (Psi)] and alimentary sugars as controls [D-glucose (Glc) and D-fructose(Fru)] were qualitatively determined by matrix-assisted laser desorption/ionization time-of-flight massspectrometry (MALDI-TOF-MS). Mass spectra revealed that the extent of glycation at lysine residueson LA with D-aldose molecules was very much higher than that of glycation with D-ketose molecules.To identify the specific site of glycation, the peptide mapping was established from protease V8digestion, using a combination of computational cutting of proteins and MALDI-TOF-MS. As comparedto peptide mapping, three and seven glycation sites were located in the primary structure of LA-ketose and LA-aldose conjugates, respectively. On the other hand, the antioxidant activities ofprotein-sugar conjugates and their peptic hydrolysates were investigated by 1,1-diphenyl-2-picrylhydrazyl radical scavenging method. The antioxidant activities of proteins/peptides glycated withrare sugars were significantly higher than those modified with the control sugars. The results indicatedthat the glycation degree and position were not markedly different between rare sugar andcorresponding control sugar, but the antioxidant properties of protein and its hydrolysate weresignificantly enhanced by modifying with rare sugar.Keywords: -Lactalbumin; rare sugar; glycation; antioxidant activity; peptide-mapping; MALDI-TOF-MS