A rotographic study of mutarotase

Abstract

No evidence was found that heavy metal ions (Cu++, Zn++, Ni++, and Hg++) catalyze the mutarotation of glucose. The strong catalytic action of mutarotase was verified. That pepsin largely destroys this activity may be taken as additional proof of the protein nature of mutarotase. alpha-Amylase had no mutarotase activity. Mutarotase catalyzes only some alphabeta transformations. Of the aldoses tested, glucose and galactose are the best substrates, indicating that the configuration at the 4th carbon atom is not important. The mutarotation of the disaccharides lactose and maltose is accelerated to a lesser degree. The lack of a hydroxymethyl group on the 5th carbon atom (xylose) also reduces the activity. The configuration at the 2d carbon atom of the sugar molecule is decisive, since neither mannose nor glucosamine serves as a substrate. This work demonstrates the general utility of automatic recording polarimetry or rotography.