02720nas a2200289   4500008004100000022001400041245015100055210006900206260008100275300002200356490000700378520163500385653001302020653001402033653001402047653002102061653001002082653002202092100003902114700002502153700002502178700002002203700002302223700002902246700002502275856013002300       2016                        eng d  a1542-641600aTargeted quantification of N-1-(carboxymethyl) valine and N-1-(carboxyethyl) valine peptides of beta-hemoglobin for better diagnostics in diabetes0 aTargeted quantification of N1carboxymethyl valine and N1carboxye  a236 GRAYS INN RD, FLOOR 6, LONDON WC1X 8HL, ENGLANDbBIOMED CENTRAL LTDcMAR  aArticle Number: 70 v133 a<p>Background: N-1-(Deoxyfructosyl) valine (DFV) beta-hemoglobin (beta-Hb), commonly referred as HbA1c, is widely used diagnostic marker in diabetes, believed to provide glycemic status of preceding 90-120 days. However, the turnover of hemoglobin is about 120 days, the DFV-beta-Hb, an early and reversible glycation product eventually may undergo irreversible advanced glycation modifications such as carboxymethylation or carboxyethylation. Hence quantification of N-1-(carboxymethyl) valine (CMV) and N-1-(carboxyethyl) valine (CEV) peptides of beta-Hb would be useful in assessing actual glycemic status. Results: Fragment ion library for synthetically glycated peptides of hemoglobin was generated by using high resolution-accurate mass spectrometry (HR/AM). Using parallel reaction monitoring, deoxyfructosylated, carboxymethylated and carboxyethylated peptides of hemoglobin were quantified in clinical samples from healthy control, pre-diabetes, diabetes and poorly controlled diabetes. For the first time, we report N-1-beta-valine undergoes carboxyethylation and mass spectrometric quantification of CMV and CEV peptides of beta-hemoglobin. Carboxymethylation was found to be the most abundant modification of N-1-beta-valine. Both CMV-beta-Hb and CEV-beta-Hb peptides showed better correlation with severity of diabetes in terms of fasting glucose, postprandial glucose and microalbuminuria. Conclusions: This study reports carboxymethylation as a predominant modification of N-1-beta-valine of Hb, and quantification of CMV-beta-Hb and CEV-beta-Hb could be useful parameter for assessing the severity of diabetes.</p>10aDiabetes10aDiagnosis10aGlycation10aGlycemic control10aHbA1c10aMass spectrometry1 aJagadeeshaprasad, Mashanipalya, G.1 aBatkulwar, Kedar, B.1 aMeshram, Nishita, N.1 aTiwari, Shalbha1 aKorwar, Arvind, M.1 aUnnikrishnan, Ambika, G.1 aKulkarni, Mahesh, J.  uhttps://library.ncl.res.in/content/targeted-quantification-n-1-carboxymethyl-valine-and-n-1-carboxyethyl-valine-peptides-beta