Structure and action of heteronemertine polypeptide toxins: inactivation of Cerebratulus lacteus toxin B-IV concomitant with tryptophan alkylation.

摘要: Abstract Reaction of Cerebratulus lacteus toxin B-IV with 2-hydroxy-5-nitrobenzyl bromide at pH 4.5 results in modification tryptophan residues and loss biological activity. With relatively small reagent excesses, one per molecule is modified without major effect on toxicity. Further reaction a second residue least 95% the toxic Modification or both significant secondary structure protein. The specificity each phase has been assessed by fingerprint analysis peptides derived from to differing extents bromide. It thus possible show that tryptophan-5 reacts first tryptophan-30 only under more rigorous conditions. appears essential for full neurotoxic