CONDENSATION OF GLYCYLGLYCINE TO OLIGOGLYCINES WITH TRIMETAPHOSPHATE IN AQUEOUS-SOLUTION .2. CATALYTIC EFFECT OF MAGNESIUM-ION

The previously reported condensation reaction of glycylglycine with tr imetaphosphate (Yamanaka et al., 1988) was reinvestigated and shown to be catalyzed by magnesium ion. Aqueous solutions containing glycylgly cine (0.5 M), trimetaphosphate (0.5 M) and magnesium chloride (0.5 M) were incubated at 38 degrees C at pH 4, 5, 6, 7 and 8. After incubatio n for ten days at pH 5, the maximum yields of tetraglycine and hexagly cine as condensation products were found to be about 12 and 1.4%, resp ectively. This result indicated the presence of a considerable catalyt ic effect of magnesium ion compared with the maximum yield of about 2% for tetraglycine and similar to 0% for hexaglycine in the absence of magnesium ion.