Premium
Identification of a labelled peptide after stoicheiometric reaction of fluorescein isothiocyanate with the Ca 2+ ‐dependent adenosine triphosphatase of sarcoplasmic reticulum
Author(s) -
Mitchinson Colin,
Wilderspin Andrew F.,
Trinnaman Brian J.,
Green N.Michael
Publication year - 1982
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(82)80710-2
Subject(s) - endoplasmic reticulum , chemistry , atpase , fluorescein isothiocyanate , peptide , fluorescein , biochemistry , reagent , isothiocyanate , lysine , adenosine triphosphatase , stereochemistry , enzyme , amino acid , fluorescence , organic chemistry , physics , quantum mechanics
Incorporation of 4.5 nmol fluorescein isothiocyanate/mg rabbit sarcoplasmic reticulum, or of 7.4 nmol/mg purified ATPase, was sufficient to inhibit the activity completely. These results are not consistent with the suggestion (Pick, U. and Karlish, S.J.D. (1980) Biochim. Biophys. Acta 626, 255–261) that 2 mol ATPase were inhibited by each mole of reagent incorporated. A single labelled peptide was purified from the inhibited ATPase and it was shown that Lys 3/190, 10 residues from the N‐terminus of tryptic fragment B, was the reactive lysine residue. This site is close to a potential nucleotide‐binding fold in the ATPase sequence. A similar peptide showing only 2 conservative replacements was isolated from the sarcoplasmic reticulum of the lobster.