DD-transpeptidase
A transpeptidase (EC 3.4.16.4) is a bacterial enzyme that cross-links the peptidoglycan chains to form rigid cell walls. This enzyme is also known by several other names including DD-peptidase, DD-transpeptidase, D-alanyl-D-alanine carboxypeptidase and serine-type D-Ala-D-Ala carboxypeptidase. In gram-positive bacteria, the peptidoglycan molecules are cross-linked by a pentapeptide bridge, whereas in gram-negative bacteria, the peptidoglycan molecules are directly covalently bound to each other.
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