FIG. 4.
Analysis of γ-PGA degradation products generated by PghP over reaction time. Reactions proceeded under standard assay conditions (see Materials and Methods). Samples (0.2 ml) after various incubation periods were applied onto Superdex peptide columns, and reaction products were monitored by absorbance at 210 nm. Molecular sizes of oligomers were estimated from elution volumes relative to those of glutamate (Mr = 147), di-γ-glutamate (Mr = 276), tetra-γ-glutamate (Mr = 535), and gastrin (Mr = 2,126). Abbreviations: Vo, void volume; G3, tri-γ-glutamate; G4, tetra-γ-glutamate; G5, penta-γ-glutamate; G7, hepta-γ-glutamate.