Amino group, alkyl stabilization

Tertiary electrophiles alkylate bydroxylamines through the SatI mechanism. These reactions (e.g. equation 10) are practically feasible only for compounds forming highly stabilized carbocations such as trityl , or 2-(p-alkoxyphenyl)propyl. All these reactions proceed exclusively on the nitrogen atom and have been used for A-protection of the amino groups in bydroxylamines. 

Chemical modification of proteins has been extensively studied over the years to identify which amino acids are involved in catalysis. Much less work has been carried out on its influence on enzyme stability. Chemical modification of proteins may yield stabilization, destabilization or no effect at all. Martinek and Berezin (1978) reported the dependence of the thermostability of chymotrypsin on the degree of alkylation of its amino groups up to 30% alkylation the stability rose slightly at 90% substitution stability increased markedly, with a maximum (110-fold) at 95% stability fell to nearly initial values when 100% amino groups were modified. (With these modifications, the optimum pH of the errzyme can change and one must therefore be cautious in comparing two different... 

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