TY - JOUR
T1 - Structural Analysis of the Minor Human Hemoglobin Components
T2 - Hb AIa1, Hb AIa2 and Hb AIb
AU - GARRICK, Laura M.
AU - McDONALD, Melisenda J.
AU - SHAPIRO, Robert
AU - BLEICHMAN, Margaret
AU - McMANUS, Michael
AU - BUNN, H. Franklin
PY - 1980/5
Y1 - 1980/5
N2 - Human hemolysate contains several minor hemoglobin components, including Hb AIa1, Hb AIa2, Hb AIb and Hb AIc which are post‐translational modifications of the major component, Hb Ao. Hb AIc is known to contain glucose attached to the N terminus of the β chains by a ketoamine linkage. We separated the α and β globin chains from purified Hb Ia1, Hb AIa2 and Hb A Ib by ion‐exchange chromatography. The β chains were reducible by sodium borohydride and gave a positive thiobarbituric acid test. These results indicated that they are modified by ketoamine‐linked carbohydrate. In addition, phosphate analysis revealed 1.5 phosphate residue associated with each β AIa1 chain and 1 phosphate residue with each β AIa2 chain. Hb AIa1, Hb AIa2 and Hb AIb were all found to be contaminated by non‐globin proteins. Protein‐sequencing approaches demonstrated that the N termini of β AIa1, β AIa2 and β AIb were blocked. In support of this conclusion, analysis of tryptic digests of β AIa2 and β AIb revealed modified N‐terminal peptides. We conclude that, like Hb AIc, components Hb AIa1, Hb AIa2 and Hb AIb also contain a sugar moiety linked to the N terminus of the β chain.
AB - Human hemolysate contains several minor hemoglobin components, including Hb AIa1, Hb AIa2, Hb AIb and Hb AIc which are post‐translational modifications of the major component, Hb Ao. Hb AIc is known to contain glucose attached to the N terminus of the β chains by a ketoamine linkage. We separated the α and β globin chains from purified Hb Ia1, Hb AIa2 and Hb A Ib by ion‐exchange chromatography. The β chains were reducible by sodium borohydride and gave a positive thiobarbituric acid test. These results indicated that they are modified by ketoamine‐linked carbohydrate. In addition, phosphate analysis revealed 1.5 phosphate residue associated with each β AIa1 chain and 1 phosphate residue with each β AIa2 chain. Hb AIa1, Hb AIa2 and Hb AIb were all found to be contaminated by non‐globin proteins. Protein‐sequencing approaches demonstrated that the N termini of β AIa1, β AIa2 and β AIb were blocked. In support of this conclusion, analysis of tryptic digests of β AIa2 and β AIb revealed modified N‐terminal peptides. We conclude that, like Hb AIc, components Hb AIa1, Hb AIa2 and Hb AIb also contain a sugar moiety linked to the N terminus of the β chain.
UR - http://www.scopus.com/inward/record.url?scp=0019306441&partnerID=8YFLogxK
U2 - 10.1111/j.1432-1033.1980.tb04581.x
DO - 10.1111/j.1432-1033.1980.tb04581.x
M3 - Article
C2 - 6772437
AN - SCOPUS:0019306441
SN - 0014-2956
VL - 106
SP - 353
EP - 359
JO - European Journal of Biochemistry
JF - European Journal of Biochemistry
IS - 2
ER -