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Is it just for historical reasons? Because the first person who did it decided to attach the C-terminus to the solid support?

Or are there chemical reasons why it would be impossible to proceed in the opposite direction?

Reto Höhener
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    It's not impossible, it's just a lot harder and much more research has been put into the C → N version. – Jan Jun 25 '15 at 09:17

1 Answers1

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The reasons are

  1. The use of an acylating agent in excess (e. g. acetic anhydride or N-acetyl imidazole) drives the reaction forward.
  2. UNCAs (urethane-type protected N-carboxy anhydrides (e. g. Fmoc, Z, Boc, ...)) can be used. They prevent racemization of the amino acid, that it is attached to.

But there are (despite of ribosomes themselves) also instances, where N -> C directionality was applied:

ste
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