New method of preparing elastase toxoid from Pseudomonas aeruginosa.

A new method for the preparation of elastase toxoid of Pseudomonas aeruginosa was developed. A chloroacetyl peptide derivative (CICH2CO-HOLeu-Ala-Gly-NH2; HOLeu, N-hydroxy-L-leucine), an active-site-directed irreversible inhibitor of Pseudomonas aeruginosa elastase, was used to prepare elastase toxoid with or without pretreatment with Formalin and L-lysine. Elastase toxoid thus obtained appeared to be ideal, possessing negligible enzyme activity while retaining full antigenicity and immunogenicity.