The amino acids will have at least one charged species at neutral pH and
that means that most of them can't cross the lipid bilayer. If amino acids
are taken in they will be transported through amino-acid permeases, but
since most microbiological media contain oligopeptides (between 2 to 8 amino
acids in length) the main mechanism for entry is through an oligopeptide
permease.
J.W. Payne wrote a review on this around 1978 in Advances in Microbial
Physiology. I've not read it in more than a decade, but I know he is a
Professor at Aberystwyth (I think!). Pd.
"Debbie" <debbie_holiday at hotmail.com> wrote in message
news:A1lQ5.173$%15.61924 at sapphire.mtt.net...
>>> How do the amino acids enter the plasma membrane?
>>
