Evidence that pyridoxal phosphate modification of lysine residues (Lys-55 and Lys-59) causes inactivation of hydroxymethylbilane synthase (porphobilinogen deaminase).
A recombinant strain of Escherichia coli has been constructed that produces approx. 200 times the amount of hydroxymethylbilane synthase found in wild-type E. coli [Hart, Abell & Battersby (1986) Biochem. J. 240, 273-276]. Enzyme purified from this strain is shown to be permanently inactivated by pyridoxal 5'-phosphate/NaB1H3(3)H1. The inactivation is not complete despite the fact that approx. 1 mol of lysine residues is modified per mol of enzyme. Evidence is gained showing that (a) modification of one of two conserved lysine residues (Lys-55 or Lys-59) results in inactivation of hydroxymethylbilane synthase and (b) these lysine residues are present in or close to the active site.
Miller
A D
AD
University Chemical Laboratory, Cambridge, U.K.
Packman
L C
LC
Hart
G J
GJ
Alefounder
P R
PR
Abell
C
C
Battersby
A R
AR
D000595:Amino Acid Sequence; D000642:Ammonia-Lyases / Q000037:antagonists & inhibitors*; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology; D011163:Hydroxymethylbilane Synthase / Q000037:antagonists & inhibitors*; D008239:Lysine / Q000378:metabolism*; D010957:Plasmids; D011480:Protease Inhibitors / Q000378:metabolism; D011732:Pyridoxal Phosphate / Q000494:pharmacology*
D011480:Protease Inhibitors; D011732:Pyridoxal Phosphate; D011163:Hydroxymethylbilane Synthase; D000642:Ammonia-Lyases; D008239:Lysine