DNA sequences can be regarded as sequences consisting of 4 symbols A
(adenine), C (cytosine), G (guanine), and T (thymine).  Many
constraints for the DNA sequences are studied because when the DNA
sequences are used as fundamental ingredients for computation or
processing information, the DNA sequences should satisfy constraints
so that molecular biological processes are done with small error
probabilities.  We show some results on the capacity of a combination
of constraints for parsing data from DNA sequences and fro chemical
reactions.