DdeI is a restriction enzyme isolated from Desulfovibrio desulfuricans, a Gram-negative
sulfate reducing soil bacteria) that can digest 1ug DNA in 1 hr @ 37C at cut site 5'C|TNAG3'
The Sickle cell mutation is in the 6th codon and changes glutamic acid (+)  to    valine(0)
        and effects the cut site.                                              5'-CTC-3'              to   5'-CAC-3' 

Dde1  Dde2