Identification, purification and partial characterization of low molecular weight protein inhibitor of Na⁺/K⁺-ATPase from pulmonary artery smooth muscle cells.
We have identified a novel endogenous low mol wt. (15.6 kDa) protein inhibitor of Na(+)/K(+)-ATPase in cytosolic fraction of bovine pulmonary artery smooth muscle cells. The inhibitor showed different affinities toward the α₂β₁ and α₁β₁ isozymes of Na(+)/K(+)-ATPase, where α₂ is more sensitive than α₁. The inhibitor interacted reversibly to the E1 site of the enzyme and blocked the phosphorylated intermediate formation. Circular dichroism study suggests that the inhibitor causes an alteration in the confirmation of the enzyme.
Department of Molecular Medicine and the Department of Biochemistry & Biophysics, University of Kalyani, Kalyani, West Bengal, 741235, India.
Sayed Modinur
SM
Rahaman
Kuntal
K
Dey
Partha
P
Das
Soumitra
S
Roy
Tapati
T
Chakraborti
Sajal
S
Chakraborti
D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D003600:Cytosol / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000302:isolation & purification*; D008970:Molecular Weight; D032389:Myocytes, Smooth Muscle / Q000201:enzymology; D011651:Pulmonary Artery / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors* / Q000737:chemistry
D004791:Enzyme Inhibitors; D000254:Sodium-Potassium-Exchanging ATPase