INACTIVATION OF CU,ZN-SUPEROXIDE DISMUTASE BY INTERMEDIATES OF MAILLARD REACTION AND GLYCOLYTIC PATHWAY AND SOME SUGARS

Human Cu,Zn-superoxide dismutase (SOD) was incubated with various inte rmediates of the Maillard reaction and glycolytic pathway (arabinose, glyoxal, glycolaldehyde, glyceraldehyde, glyceraldehyde 3-phosphate, a nd dihydroxyacetone) and some reducing sugars (sorbose, xylose, and ri bose), The change of the activity and the molecular weight were measur ed and compared with that of SOD incubated with glucose or fructose, S orbose, xylose, and ribose decreased the activity with a rate comparab le to fructose. Site-specific and random fragmentation were observed u pon the incubation with them, Arabinose showed a similar inactivation rate as glucose. The intermediates other than arabinose had a high ina ctivation rate. Especially, glyceraldehyde, glycolaldehyde, and glyoxa l most strongly lowered the activity in a concentration-dependent mann er and a significant inactivation was recognized even at 1 mM level, S DS-PAGE band patterns indicated that the inactivation by those carbony l compounds occurred by both crosslinking and site-specific fragmentat ion of SOD.