Modification of polynucleotides by a fragment produced by enzymatic cleavage of S-(1, 2-dichlorovinyl)-L-cysteine

Polyribo- and polydeoxyribonucleotides were allowed to react with ³⁵S-(1,2-dichlorovinyl)-L-cysteine (DCVC) in presence of a bovine kidney lyase yielding products which were substituted to varying degrees with an alkylating thiovinyl fragment (AF) released from DCVC. Polydeoxyribonucleotides were more extensively substituted than polyribonucleotides. Double stranded homopolymer pairs were much less effective as acceptors of (AF) than single stranded polymers. Nucleotide substitution occurred only at the polymer level. Enzymatic hydrolysis of (AF)-substituted polymers yielded dinucleotides which contained an (AF) fragment apparently covalently linked in unknown fashion. (AF)-substituted polynucleotides had reduced ability to form helical complexes with complementary polynucleotides, as revealed by hypochromicity, melting transition and renaturation.