Introduction to Enzyme and Coenzyme Chemistry - E-Library Home

5 Enzymatic Hydrolysis and Group
Transfer Reactions
5.1 Introduction
Hydrolysis reactions are fundamental to cellular metabolism. In order to break
down biological foodstuVs into manageable pieces that animals can utilise for
energy, they must have enzymes capable of hydrolysing biological macromolecules.
Thus, many of the hydrolytic enzymes that we shall meet in this chapter
are involved in digestive processes. However, that is by no means the only area
in which we shall encounter hydrolase enzymes.
We shall look in turn at enzymes that hydrolyse each of the three major
classes of biological macromolecules: polypeptides, polysaccharides and nucleic
acids. More detailed discussions of the structures and chemistry of these macromolecules
can be found in most advanced chemistry or biochemistry texts. The
classes of enzymes that hydrolyse these molecules are shown in Table 5.1:
Table 5.1 Classes of hydrolase and group transfer enzymes.
Group
transferred Hydrolase Transferase
Acyl
O
C
NHR
O
C
OH + RNH 2
Peptidase
Amidase
Protease
Transpeptidase
O
C
OR
O
C
OH
+ ROH
Esterase
Lipase
Acyl transferase
Glycosyl
HOH 2 C
RO'
HO
O
OH
OR
HOH 2 C
RO'
HO
O
OH
OH
+ ROH
Glycosidase Glycosyl transferase
Phosphoryl
O
O
P OR P OH + ROH
O − O −
Phosphatase
Nuclease
Phosphodiesterase
Kinase
Phosphotransferase
81