A simple model of reducing and nonreducing sugars

A Simple Model of Reducing and Wonreducing Sugars A simple hut effective method of illustrating anomers, reducing and nonreducing disaeeharides such as sucrose (left) and mutarotation of such compounds as glucose (right)

I

HO-C-H

HO-C-H

H-C

I

CHaOH

H-C-0

I

CHXOH

HO-C-H

=

I

H-C-OH H-C

I

I

CHzOH

H-C-OH

I

HO-C-H

H-C

CHIOH

I

CHzOH

uses i woagile volunteersfrom the class. Onestudent is directed tograsp his legjust above the ankle with his right hand and the ocher to perform the same operation but using his left hand; these human models represent the two anomers of a pyranose (or furanose) structure. Mutarotation is illustrated by having each student reverse the hand grasping his ankle. Have the two students clasp their free hands to illustrate a nonreducing sugar like a-D-glueopyranosyl-m-fruetofuranoside. Finally have the students release each other's hands and have one grasp the other just below the knee (while each maintains a firm grip on his own leg) to illustrate a reducing disaccharide capable of undergoing mutarotation. This process could be extended using several students to illustrate a portion of a cellulose molecule or of the amylase fraction of ~tarch.The students enjoy this tension-easing exercise and the material is presented in an easily remembered form.

Peggy W. Alley Amarillo College PO Box 447 Amarillo. TX 79178

Volume 63

Number 3

March 1986

231