AGGREGATES OF PEPTIDE-CONTAINING BLOCK-COPOLYMERS AND THEIR INTERACTIONS WITH A LIPASE IN AQUEOUS-SOLUTION

Peptide-containing block copolymers -acetyliminoethylene)-block-poly(L -phenylalanine)s (1) form water-soluble large aggregates in water due to the hydrophobic and hydrogen-bonding nature of the poly(L-phenylala nine) block. The solution properties were studied by size exclusion ch romatography, dynamic light scattering, H-1 NMR spectroscopy, and tran smission electron microscopy. The results were compared with those of the block copolymers iminoethylene)-block-poly(N-benzoyliminoethylene) s (2) as analogous structures of poly(L-phenylalanine). The peptide co ntaining block copolymers 1 form aggregates in water even though only short segments of poly(phenylalanine) are provided. The hydrogen-bondi ng character of the amide bond in the poly(phenylalanine) segment may induce strong interactions with each polymer chain in water. The inter action of Lipase P with the polymer aggregates in water was studied by means of size exclusion chromatography. The aggregates have a strong capability of incorporating Lipase P and largely increase the hydrolys is activity of Lipase P against p-nitrophenyl propionate compared with free Lipase. The guest-binding ability of 8-anilino-1-naphthalenesulf onic acid for the polymer aggregates was also studied.