Effects of aminoguanidine and pyridoxal phosphate on glycation reaction of aspartate aminotransferase and serum albumin.
Effects of aminoguanidine (AG) on binding of glucose and pyridoxal phosphate (PLP) to albumin, and on glycation reaction of cytosolic aspartate aminotransferase (cAST) were examined in an in vitro system. AG was found to inhibit not only glycation of albumin but binding of PLP to albumin, indicating that distribution of PLP into tissues is inhibited by AG. AG bound to PLP directly to produce a new compound, and in this manner AG inhibited cAST activity. AG could also inhibit glycation of cAST and the extent of inhibition was varied with sugars used. It appears that, although AG is a useful inhibitor of glycation proteins, it may be toxic from the viewpoints of vitamin B6 as an essential nutrient and also PLP-dependent enzymes.
Okada
M
M
Faculty of Health and Living Sciences, Naruto University of Education, Japan.
Ayabe
Y
Y
D000818:Animals; D001219:Aspartate Aminotransferases / Q000032:analysis / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D005947:Glucose / Q000378:metabolism; D006146:Guanidines / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D011732:Pyridoxal Phosphate / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012709:Serum Albumin / Q000378:metabolism*
D006146:Guanidines; D012709:Serum Albumin; D011732:Pyridoxal Phosphate; D001219:Aspartate Aminotransferases; D005947:Glucose; C004479:pimagedine