Identification of a highly reactive sulphydryl group in human placental glutathione transferase by a site-directed fluorescent reagent.
A fluorescent maleimide derivative, N-(4-anilino-1-naphthyl) maleimide (ANM), a specific probe for thiol groups, reacted with human placental glutathione transferase (GST, EC 2.5.1.18), causing a complete inactivation of the enzyme in a few minutes. The modified enzyme was denatured, alkylated and digested with (L-1-tosylamide-2-phenylethyl chloromethyl ketone)-trypsin. The tryptic digest was analysed by HPLC and a fluorescent peptide was obtained. The sequence of this peptide allowed us, by a comparison with a well known primary structure, to assign the position 47 to the most reactive cysteine of GST enzyme.
Lo Bello
M
M
Department of Biology, University of Rome, Tor Vergata, Italy.
Petruzzelli
R
R
De Stefano
E
E
Tenedini
C
C
Barra
D
D
Federici
G
G
D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D005456:Fluorescent Dyes; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008301:Maleimides; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D010920:Placenta / Q000201:enzymology*; D013438:Sulfhydryl Compounds / Q000032:analysis
D005456:Fluorescent Dyes; D008301:Maleimides; D010446:Peptide Fragments; D013438:Sulfhydryl Compounds; C010854:N-(1-anilinonaphthalyl)-4-maleimide; D005982:Glutathione Transferase