English to Portuguese Science Chemistry; Chem Sci/Eng química orgânica

Preciso de sugestões em PT/BR para as expressões "site"/"basic site" no seguinte contexto:

"In an acid mechanism, the first thing you want to look for is a site on the molecule that can be protonated. The only basic site on the starting material in this case is the alcohol, so the first step would be protonation of the alcohol group by sulfuric acid".

Agradeço antecipadamente.