The poly-l-lysine acid hydrolysate was evaporated in a Speed Vac concentrator (Savant Instruments, Hicksville, NY), and 63 mg was dissolved in 8 ml of 0.2 mpyridine formate (pH 3.25) and loaded onto a cation exchange column (3 × 15 cm, Dowex 50WX8–400). Fractions of 5 ml were ...