Reconstitution Study of sGDH with PQQ Adducts and Substrate and Product Analogs.
Sum Cheung 
Faculty Advisor: Tetsuo Otsuki

     Soluble glucose dehydrogenase (sGDH) is a homodimer that requires two cofactors, one pyrroloquinoline quinone (PQQ) and two Ca²⁺ cations per monomer subunit, to oxidize aldoses. The steady-state kinetics study of sGDH shows indications of cooperativity at higher substrate concentration. The observed cooperativity could originate from conformational changes in one subunit of the enzyme, for example, in the presence of a substrate, product, or intermediate, which would induce changes in the second subunit, consequently, the enzymatic activity. Our approach includes (1) the synthesis of an adduct of PQQ mimicking an intermediate of PQQ during the enzymatic reaction and the examination of the kinetic behavior of partially reconstituted sGDH with the adduct, and (2) the study of the steady-state kinetics of normal sGDH in the presence of a substrate or product analog.