introducing alanine mutations - (Mar/06/2010 )

Hi,

why is it that when you introduce a mutation using pcr that most mutations involve changing the normal codon sequence to an alanine codon sequence?
(im very new to doing lab work and methods)

Alanine is the most typical, benign side group amino acid. It's uncharged, relatively small, non-reactive. Glycine might be another choice, but it is so small that it allows rotation, possibly introducing folding issues. So, most people attempting to determine active sites and important residues scan the protein replacing each amino acid with alanine mutations.