Improvement of catalytic antibody activity by protease processing.

An immunoglobulin L chain (HIR) was treated with lysyl-endopeptidase. Gel filtration chromatography of the digestion mix identified a peak displaying a significantly higher specific catalytic activity than that of the original sample. The protein in the peak was 11 kDa in size and constituted the VL fragment of HIR. The Km and Kcat values of Chromozym TRY hydrolysis for HIR were 1.5 x 10(-4) M and 6.2 min(-1), and for the VL fragment 7.3 x 10(-4) M and 4.8 x 10(2) min(-1), respectively. Three out of the five BJPs studied in this paper displayed elevated catalytic activity after processing with lysyl-endopeptidase. Similar results were also obtained for the complete antibody.