AN ELONGATED FORM OF T4 GLUTAREDOXIN WITH 4 EXTRA RESIDUES

Two different forms of T4 glutaredoxin (thioredoxin) arising from the same gene on a multicopy plasmid in an Escherichia coli expression sys tem have been isolated and characterized. Up to one-fourth of purified T4 glutaredoxin has an extension of four amino acids in the carboxy t erminus, with the sequence aspartate, arginine, isoleucine, lysine. Th is four-residue extension may be caused by a translational +1 frameshi ft at the UGA terminator codon.