[Interaction of muscle glycogen phosphorylase B with flavin-adenine dinucleotide and its analogs].
The inhibition of rabbit skeletal muscle glycogen phosphorylase b by FAD and its analogues with substitutes in the position 8 has been studied. The value of half-saturation, [I]0,5, for inhibitors increases in the following order: FAD (44 microM), 8 alpha-hydroxy-FAD (60 microM), 8-dimethylamino (nor)-FAD (69 microM), 8 alpha-(N-acetyl-L-cystein-S-yl)-FAD (106 microM). From the comparison of these values with those obtained earlier for FMN analogues, it follows that in the case of FAD the half-saturation value is less sensitive to modification of the position 8 in the flavin isoalloxazine ring. The existence of the glycogen phosphorylase b FAD-complex has been proved by the spectrophotometry and sedimentation methods. The positions of maxima of optical absorption of the enzyme-bound FAD in the 300-500 nm region are identical with corresponding positions for FMN. FAD has been shown to hinder the AMP-induced transition of dimeric form of the enzyme to tetrameric one.
D000818:Animals; D001665:Binding Sites; D005182:Flavin-Adenine Dinucleotide / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D009132:Muscles / Q000201:enzymology*; D010763:Phosphorylase b / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006005:Phosphorylases / Q000037:antagonists & inhibitors*; D011817:Rabbits; D013053:Spectrophotometry
D005182:Flavin-Adenine Dinucleotide; D010763:Phosphorylase b; D006005:Phosphorylases
Vzaimodeĭstvie myshechnoĭ glikogenfosforilazy B s flavinadenindinukleotidom i ego analogami.