Amino acid nitrosation products as alkylating agents

Nitrosation reactions of alpha-, beta-, and gamma -amino acids whose reacti on products can act as alkylating agents of DNA were investigated. To appro ach in vivo conditions for the two-step mechanism (nitrosation and alkylati on), nitrosation reactions were carried out in aqueous acid conditions (mim icking the conditions of the stomach lumen) while the alkylating potential of the nitrosation products was investigated at neutral pH, as in the stoma ch lining cells into which such products can diffuse. These conclusions wer e drawn: (i) The alkylating species resulting from the nitrosation of amino acids with an -NH2 group are the corresponding lactones, (ii) the sequence of alkylating power is: alpha -lactones > beta -lactones > gamma -lactones , coming respectively from the nitrosation of alpha-, beta-, and gamma -ami no acids; and (iii) the results obtained may be useful in predicting the mu tagenic effectiveness of the nitrosation products of amino acids.