Erythrosin 5'-isothiocyanate labels Cys549 as part of the low-affinity ATP binding site of Na+/K+-ATPase.
The high-affinity E1ATP site of Na+/K+-ATPase labeled with fluorescein 5'-isothiocyanate and its E2ATP site labeled with erythrosin 5'-isothiocyanate (ErITC), as was shown recently [Linnertz et al. (1998) J. Biol. Chem. 273, 28813-28821], reside on separate and adjacent catalytic alpha subunits. This paper provides evidence that specific labeling of the E2ATP binding site with ErITC resulted in a modification of the Cys549 residue in the tryptic fragment with the sequence Val545-Leu-Gly-Phe-Cys549-His550. Hence, Cys549 is part of or close to the low-affinity E2ATP binding site of Na+/K+-ATPase.
Linnertz
H
H
Institute of Biochemistry and Endocrinology, Justus-Liebig University Giessen, Germany.
Kost
H
H
Obsil
T
T
Kotyk
A
A
Amler
E
E
Schoner
W
W
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D020134:Catalytic Domain; D003545:Cysteine; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004923:Erythrosine / Q000031:analogs & derivatives / Q000494:pharmacology; D016650:Fluorescein-5-isothiocyanate / Q000494:pharmacology; D017879:Isothiocyanates / Q000494:pharmacology; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry* / Q000378:metabolism*; D013552:Swine
D004791:Enzyme Inhibitors; D017879:Isothiocyanates; D010446:Peptide Fragments; C022232:erythrosine isothiocyanate; D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase; D016650:Fluorescein-5-isothiocyanate; D003545:Cysteine; D004923:Erythrosine