Removal of catalytic activity by EDTA from antibody light chain

Gp41 peptide antigen of the HIV-1 envelope (TP41-1:TPRGPDRPEGIEEEGGERDR, a highly conserved region) was enzymatically degraded by the antibody light c hain 41S-2-L after an induction period. The peptide bond between Glu(14) an d Gly(15) was cleaved early in the reaction. When EDTA was added in the ind uction period, it inhibited the degradation of TP41-1 thus ceasing the cata lytic activity of 41S-2-L. In contrast, when EDTA was added after the induc tion period, only a small reduction in the catalytic activity was observed. These observations suggest that metal ions are important in stimulating ca talytic activity early in the reaction.