J. Biol. Chem., Vol. 261, Issue 10, 4499-4503, Apr, 1986
Identification of tyrosine and lysine peptides labeled by 5'-p- fluorosulfonylbenzoyl adenosine in the active site of pyruvate kinase
DL DeCamp and RF Colman
The nucleotide affinity label 5'-p-fluorosulfonylbenzoyl adenosine reacts
at the active site of rabbit muscle pyruvate kinase, with irreversible
inactivation occurring concomitant with incorporation of about 1 mol of
reagent/mol of enzyme subunit (Annamalai, A. E., and Colman, R. F. (1981)
J. Biol. Chem. 256, 10276-10283). Purified peptides have now been isolated
from 70% inactivated enzyme containing 0.7 mol of reagent/mol of enzyme
subunit. Rabbit muscle enzyme labeled with radioactive
5'-p-fluorosulfonylbenzoyl adenosine was digested with thermolysin.
Nucleosidyl peptides were purified by chromatography on
phenylboronate-agarose and reverse-phase high performance liquid
chromatography. After amino acid and N-terminal analysis, the peptides were
identified by comparison with the primary sequences of chicken and cat
muscle enzyme. About 75% of the reagent incorporated was distributed
equally among three O-(4-carboxybenzenesulfonyl)tyrosine- containing
peptides: Leu-Asp-CBS-Tyr-Lys-Asn, Val-CBS-Tyr, and Leu-Asp-
Asn-Ala-CBS-Tyr. These tyrosines are located in a 28-residue segment of the
530-amino acid sequence. The remainder of the incorporation was found in
two N epsilon-(4-carboxybenzenesulfonyl)lysine-containing peptides.
Leu-CBS-Lys and Ala-CBS-Lys-Gly-Asp-Tyr-Pro. Modification in the presence
of MnATP or MnADP resulted in a marked decrease in labeling of these
peptides in proportion to the decreased inactivation. It is suggested that
these modified residues are located in the region of the catalytically
functional nucleotide binding site of pyruvate kinase.