Open AccessThe Mitochondrial ATPase
Author(s) -
FERGUSON Stuart J.,
LLOYD William J.,
RADDA George K.
Publication year - 1975
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1975.tb04121.x
Subject(s) - chemistry , residue (chemistry) , atpase , tyrosine , enzyme , nucleotide , protein subunit , fluorescence , biochemistry , stereochemistry , physics , quantum mechanics , gene
1 When mitochondrial ATPase, which has been modified on a single tyrosine residue by 4‐chloro‐7‐nitrobenzofurazan, is incubated at pH 9.0, the 7‐nitrobenzofurazan group undergoes an intramolecular transfer to a nitrogen residue. The rate of this transfer is sensitive to the binding of adenine nucleotides to the enzyme. The resulting N ‐nitrobenzofurazan ATPase has little or no activity. 2 The fluorescence of the N ‐nitrobenzofurazan group in the modified ATPase is quenched on binding of ADP. 3 Electrophoresis of the modified enzyme in sodium dodecyl sulphate on a 10% polyacrylamide gel shows that the fluorescence of the N ‐nitrobenzofurazan chromophore is exclusively in the β subunit. 4 The rate of transfer of the nitrobenzofurazan group from tyrosyl oxygen to nitrogen on the enzyme is compared with the rate of transfer between model compounds. 5 The interaction of the N ‐nitrobenzofurazan ATPase with aurovertin is reported.