Impurities in commercial xanthine oxidase inhibit Ca pump and interfere in contractility of pig coronary artery.
Commercial, but not pure, preparations of xanthine oxidase in the absence of an aldehyde or xanthine were observed to inhibit Ca-uptake by the subcellular membranes isolated from the smooth muscle of the pig coronary artery. This inhibition was not due to xanthine oxidase but a contaminant in the preparation. The commercial preparation caused a greater relaxation of the PGF2 alpha contracted coronary artery than the pure enzyme. The tissues treated with the commercial xanthine oxidase partially lost the ability to contract subsequently to PGF2 alpha.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors*; D002499:Centrifugation, Density Gradient; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D010070:Oxalates / Q000494:pharmacology; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D013552:Swine; D014969:Xanthine Oxidase / Q000494:pharmacology / Q000592:standards*
D010070:Oxalates; D014969:Xanthine Oxidase; D000252:Calcium-Transporting ATPases; D002118:Calcium