NMR studies of pig gastric microsomal H+,K+-ATPase and phospholipid dynamics. Effects of ethanol perturbation.
The effects of ethanol on the gastric H+,K+-ATPase activity and the degree of mobility of various microsomal phospholipids were assessed using 31P and 1H NMR. This illuminated the role of lipid-protein association in the function of pig gastric microsomes. Treatment of gastric microsomes with 15% ethanol for 1 min at 37 degrees C inactivated the H+,K+-ATPase activity, which could largely be reconstituted by supplementation with phosphatidylcholine isolated from the gastric microsomes. Under similar conditions, the 1H NMR profile of the microsomal +N(CH3)3 choline moiety showed dramatic enhancement of peak intensity as well as a break point at 25 degrees C which was restored to the untreated control value after reconstitution. This break, together with the dramatic enhancement in the overall lipid profile, compared to the control and reconstituted microsomes, suggested a greater degree of freedom of movement of the microsomal lipids following ethanol perturbation. The data demonstrate the unique ability that a combined approach using 31P and 1H NMR holds as a noninvasive probe to study the structure-function relationship of biomembranes.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D000431:Ethanol / Q000494:pharmacology*; D005753:Gastric Mucosa / Q000201:enzymology / Q000648:ultrastructure*; D017506:H(+)-K(+)-Exchanging ATPase; D008274:Magnesium / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D008861:Microsomes / Q000201:enzymology; D010713:Phosphatidylcholines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D013552:Swine; D013696:Temperature
D010713:Phosphatidylcholines; D010743:Phospholipids; D000431:Ethanol; D000251:Adenosine Triphosphatases; D017506:H(+)-K(+)-Exchanging ATPase; D008274:Magnesium; D011188:Potassium