Peptide Bond formation between successive amino acids
(A) The amino
end on the second (R2)
amino acid is added to the carboxyl end of the first (R1)
amino acid.
In the in vitro reaction, an O from
the carboxyl end combines with two protons (H)
from the amino acid to form a single water molecule (H2O).
The condensation product leaves a covalent peptide
bond (O=C-N-H). (B) Because
succesive amino acids are added to the carboxyl end of
the polypeptide, and the amino terminus of the R1
amino acid remains
unchanged, the polypeptide is said to grow in the N
C
direction.
Each of the repeating ( -N-C(R)-C- ) subunits
remaining after the dehydration reaction is an amino
acid residue.
C
direction.
Each of the repeating ( -N-C(R)-C- ) subunits
remaining after the dehydration reaction is an amino
acid residue. Figure © 2012 TA Brown, Introduction to Genetics (1st ed.); additional text © 2012 by Steven M. Carr