ADP tethered to tyrosine-beta 345 at the catalytic site of the bovine heart F1-ATPase is converted to tethered AMP by Mg(2+)-dependent hydrolysis when the enzyme is photoinactivated with 2-N3-ADP.
Comparison of profiles of radioactive peptides resolved by HPLC from tryptic digests of the bovine heart F1-ATPase depleted of nucleotides (nd-MF1) which had been photoinactivated with 2-N3-[beta-32P]ADP, on the one hand, and 2-[8-3H]ADP, on the other, shows that the beta phosphate of ADP tethered to tyrosine-beta 345 is slowly hydrolyzed in the presence of Mg2+. When nd-MF1 was photoinactivated with 2-N3-[8-3H]ADP in the absence of Mg2+, hydrolysis of the beta phosphate from ADP tethered to tyrosine-beta 345 was not observed. Subsequent addition of Mg2+ initiated conversion of ADP tethered to tyrosine-beta 345 to tethered AMP suggesting that functional groups at the catalytic site participate in the hydrolytic reaction.
Jault
J M
JM
Department of Chemistry, University of California at San Diego, La Jolla 92093-0601.
Allison
W S
WS
D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D000249:Adenosine Monophosphate / Q000031:analogs & derivatives / Q000096:biosynthesis*; D000345:Affinity Labels; D000818:Animals; D001386:Azides / Q000494:pharmacology; D002417:Cattle; D006868:Hydrolysis; D008027:Light; D008274:Magnesium / Q000494:pharmacology; D008929:Mitochondria, Heart / Q000201:enzymology; D010777:Photochemistry; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects
D000345:Affinity Labels; D001386:Azides; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; C022295:2-azidoadenosine 3',5'-diphosphate; D006180:Proton-Translocating ATPases; D008274:Magnesium