Fractions isolated with the elution gel electrophoresis
and centrifugation procedures were hydrolyzed using
6N HCl (110 °C for 18 h), and the constituent amino
acids in the hydrolysate were puriWed by cation
exchange chromatography (Dowex 50W 8X; Bio-Rad).
Amino acids were eluted with 4M NH4OH and dried
in a SpeedVac (Savant Instruments Inc., Holbrook,
NY). Amino acids were thereafter derivatized as their
N-acetyl-propyl.