In-depth comparative characterization of hemoglobin glycation in normal and diabetic bloods by LC-MSMS.
J Am Soc Mass Spectrom
; 25(5): 758-66, 2014 May.
Article
de En
| MEDLINE
| ID: mdl-24578002
ABSTRACT
The glycation level at ß-Val-1 of the hemoglobin ß chain in human blood (HbA1c%) is used to diagnose diabetes and other diseases. However, hemoglobin glycation occurs on multiple sites on different isoforms with different kinetics, but its differential profile has not been clearly demonstrated. In this study, hemoglobin was extracted from the blood of normal and diabetic individuals by protein precipitation. Triplicate solutions prepared from each sample were directly analyzed or digested with multiple enzymes and then analyzed by nano-LC/MS via bottom-up approach for side-by-side characterization. Intact hemoglobin analysis indicated a single glucose-dominant glycation, which showed good correlation with the HbA1c% values. Moreover, full sequence (100%) of α/ß globin was mapped and seven glycation sites were unambiguously assigned. In addition to ß-Val-1, two other major sites at α-Lys-61 and ß-Lys-66, which contain the common sequence HGKK, and four minor sites (<1%) on α-Val-1, ß-Lys-132, α-Lys-127, and α-Lys-40 were identified. All sites were shown to exhibit similar patterns of site distribution despite different glucose levels. Both the intact mass measurement and bottom-up data consistently indicated that the total glycation percentage of the ß-globin was twice higher than the α-globin. Using molecular modeling, the 3D structure of the consensus sequence (HGKK) was shown to contain a phosphate triangle cavity, which helps to catalyze the glycation reaction. For the first time, hemoglobin glycation in normal and diabetic bloods was comparatively characterized in-depth with 100% sequence coverage. The results provide insight about the HbA1c parameter and help define the new and old markers.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Hémoglobine glyquée
/
Modèles moléculaires
/
Diabète
/
Globines bêta
Type d'étude:
Prognostic_studies
Limites:
Humans
Langue:
En
Journal:
J Am Soc Mass Spectrom
Année:
2014
Type de document:
Article
Pays d'affiliation:
Taïwan