Poster 15: Human hemoglobin is a tetrameric protein containing two α and two β globins, each with a hemeprosthetic group in a deep cavity. The primary function of hemoglobin is to load oxygen at the lungs and release it at the tissues for cellular respiration. In normal red cells, around 5% of hemoglobin is found with a glucose adduct; this form of the protein is designated hemoglobin A1c. The glucose attachment is a posttranslational modification formed in vivo by a nonenzymatic reaction of glucose onto the N-terminus of the β chain. HbA1c serves as a measurement of the average blood sugar level over an extended period of time. Elevated levels of glycated hemoglobin are correlated to hyperglycemia, and consequently HbA1c is currently used as the definitive marker for unmanaged diabetes. Our research investigated the action of a highly active sugar, ribose-5-phosphate (R5P), as a hemoglobin glycating agent. Using LC-MS and SDS PAGE, we show the reaction between hemoglobin and R5P to be quite rapid and to form covalent crosslinks between hemoglobin monomers.
