[Functionally important residues of glutamic acid in E. coli pyrophosphatase. I. Chemical modification and localization in the primary structure].
Inorganic pyrophosphatase of E. coli is rapidly and irreversibly inactivated by 5-ethyl-5-phenylisoxazolium-3'-sulfonate (Woodward's reagent K). The appearance in the absorption spectrum of a maximum at 340 nm testifies to the formation of an enzyme enol ester with the inhibitor. The non-hydrolyzable substrate analog CaPP1 partly protects the enzyme from inactivation. A peptide has been isolated from a tryptic hydrolysate of inactivated enzyme which contains an amino acid residue whose modification is critical for the enzyme activity. This peptide corresponds to residues 95-104 of pyrophosphatase and contains four dicarboxylic acid residues. A peptide containing a modified glutamic acid residue was isolated from modified pyrophosphatase hydrolyzed by protease v8. This peptide represents a fragment of a tryptic modified peptide and has a Glu-Ala-Gly-Glu (residues 98-1C1) structure. It is concluded that inactivation of E. coli pyrophosphatase by Woodward's reagent K is a result of selective modification of Glu98, apparently by the most reactive dicarboxylic amino acid within the enzyme active center.
Raznikov
A V
AV
Egorov
Ts A
TsA
Mirgorodskaia
O V
OV
Skliankina
V A
VA
Avaeva
S M
SM
D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000201:enzymology*; D005971:Glutamates / Q000737:chemistry*; D018698:Glutamic Acid; D043564:Inorganic Pyrophosphatase; D008969:Molecular Sequence Data; D011755:Pyrophosphatases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity
D005971:Glutamates; D018698:Glutamic Acid; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase
Funktsional'no vazhnyĭ ostatok glutaminovoĭ kisloty v pirofosfataze E. coli. I. Khimicheskaia modifikatsiia i lokalizatsiia v pervichnoĭ strukture.