[vernii]

During the formation of a peptide bond, H2O is released. H+ is taken from NH2 and OH- from COOH( but it acts as acid right?, Then how?)

[Babcock_Hall]

Do you mean how is a peptide bond biologically synthesized or how is it formed when a peptide chemist makes one?

[Borek]

I believe OP has problems with the mechanism, that's what I gather from the earlier question about sulphonyl chloride reaction with NaOH.

[Babcock_Hall]

@OP, It is not practical to make a peptide bond from two free amino acids.*  Instead, the Carboxylic acid is made into a derivative.  Regarding the biochemical synthesis of peptide, what is done is to make what an organic chemist might call an active ester, an ester with a hydroxyl group of transfer RNA.
*I suppose that one could draw out the mechanism for acid-catalyzed or base-promoted hydrolysis of a peptide bond.  The mechanism of formation would be the reverse, but the equilibrium favors hydrolysis.