Effect of nonenzymatic glycation on the autooxidation kinetics of adult human hemoglobin

CHED 208

Richelle M. Raagas, richelletz@gmail.com1, Damon M. Robles2, and Raymond M. Esquerra1. (1) Department of Chemistry and Biochemistry, San Francisco State University, 1559B Sloat Blvd. #175, San Francisco, CA 94132, (2) City College of San Francisco, San Francisco, CA 94132
Diabetics have elevated levels of glycated hemoglobin (hemoglobin with a covalently linked sugar). Understanding how glycation affects the function and stability of hemoglobin may help elucidate the course of diabetic complications. We examined how glycation affects the rate at which hemoglobin auto-oxidizes to methemoglobin. We used absorption spectroscopy to compare the auto-oxidation kinetics of purified HbA0 (non-glycated hemoglobin) and HbA1c (glycated hemoglobin). Our results show that HbA1c auto-oxidizes at a considerably slower rate than HbA0. Since HbA in the presence of inositol hexaphosphate, an allosteric effector, auto-oxidizes faster than HbA that is stripped of allosteric effectors, we propose that glycation alters the auto-oxidation of hemoglobin by inducing a structural change that disrupts normal quaternary interactions. Because glycated residues and metals are known to generate reactive oxygen species, future directions include determining how auto-oxidation kinetics of hemoglobin is influenced by the combination of metals and glycation.
 

Undergraduate Research Poster Session
2:30 PM-4:30 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Chemical Education

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007