Low and high Km forms of dinitrophenylglutathione-stimulated ATPase in bovine lens.
Dinitrophenyl S-glutathione (Dnp-SG) ATPase which catalyses the hydrolysis of ATP in the presence of GSH-conjugates has been implicated previously in the transport of these conjugates. In the present studies we demonstrate that Dnp-SG ATPase is present in bovine lens epithelium and cortex. The specific activity per mg membrane protein was found to be 75-fold higher in the epithelium as compared to the cortex. No enzyme was detected in the nuclear region of the lens. Dnp-SG ATPase was purified from bovine lens epithelium and cortex using Dnp-SG-Sepharose 6MB affinity chromatography. The partially purified Dnp-SG ATPase had two distinct Km values, 120 microM and 1.0 mM. The antibodies raised against human erythrocyte Dnp-SG ATPase cross-reacted with the bovine lens epithelium Dnp-SG ATPase which was identified by Western blot as a band corresponding to an approximate M(r) value of 80,000 Da.
Kumari
K
K
Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston 77555.
Ansari
N H
NH
Saxena
M
M
Awasthi
Y C
YC
Srivastava
S K
SK
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D004591:Electrophoresis, Polyacrylamide Gel; D007903:Lens Capsule, Crystalline / Q000201:enzymology; D007904:Lens Cortex, Crystalline / Q000201:enzymology*; D008565:Membrane Proteins / Q000032:analysis
D008565:Membrane Proteins; D000251:Adenosine Triphosphatases; C068387:S-(dinitrophenyl)glutathione ATPase