THE STUDIES OF MICROWAVE EFFECTS ON THE CHEMICAL-REACTIONS

Microwave heating involves direct absorption of energy by functional g roups that bear ionic conductivity or a dipole rotational effect, and this energy is then released into the surrounding solution. This absor ption of energy causes the functional groups involved to have higher r eactivity to other surrounding reactants than when they are simply inc ubated with the reactants at the same temperature. In other word the e nhanced rate of the reaction can be due to the reactant stirred by the molecular dipole rotation and molecules themselves acting as a stirri ng bar. In contrast to conventional heating, the salient feature of '' dipole rotation'' constitutes one efficient form of ''molecular agitat ion'' or ''molecular stirring'' many aspects of which can be explore i n chemical reactions. We will discuss some of the useful applications of this ''molecular agitation'' by means of microwave irradiation. Usi ng this unique technology, we have developed: 1) a method to control t he cleavage sites of peptide bonds, especially those bonds connected t o aspartic acid residues inside the native peptides and proteins, 2) a method to increase coupling efficiency in solid-phase peptide synthes is using a common microwave oven, 3) a novel procedure that increases the rate of alcalase-catalyzed reactions using microwave irradiation i n peptide-bond formation with proline as a nucleophile and selective b enzoylation of a pyranoside derivative, 4) a procedure to solubilize a nd hydrolyze retrograded starch, 5) a novel procedure to enhance the r ate of saponification in a serum sample for very long chain fatty acid analysis.