tokens: Fourth , extensive purification by several cycles of TRE -DNA affinity chromatography resulted in the 32 , 36 to 42 and 110 kD proteins and to less extent the 50 kD factor .
folded_tokens: fourth , extensive purification by several cycles of tre -dna affinity chromatography resulted in the 32 , 36 to 42 and 110 kd proteins and to less extent the 50 kd factor .
labels: O O O O O O O O B-DNA_domain_or_region O O O O O O O O O O O O O O O O O O O O B-protein_molecule I-protein_molecule I-protein_molecule O