Industrial Biotransformations

EC 2.8 Transferring sulfur-containing groups
R S + A
R + A S
A = acceptor, e.g. cyanide, phenols, alcohols, carboxylic acids, amino acids, amines, saccharides
R = sulfur atom, (phosphorous-) organic residue
2-
S = sulfur atom, SO3 , SH, CoA
EC 2.9 Transferring selenium-containing groups
HO
O
NH 2
O
tRNA
Se
+ O P O
HSe
O
O
NH2 O
tRNA + O
O
P O
2.2 Enzyme Classes
The only enzyme classified under this subclass is l-seryl-tRNA (Sec) selenium transferase.
2.2.3
EC 3 Hydrolases
This third main class of enzymes plays the most important role in today’s industrial
enzymatic processes. Hydrolases catalyze the hydrolytic cleavage of C–O, C–N, C–C and
some other bonds, including P–O bonds in phosphates. The applications of these
enzymes are very diverse: the most well-known examples are the hydrolysis of polysaccharides,
nitriles (see the processes on pages 317 and 320), proteins or the esterification
of fatty acids (see the process on page 297). Most of these industrial enzymes are used in
processing-type reactions to degrade proteins, carbohydrates and lipids in detergent formulations
and in the food industry.
Interestingly, all hydrolytic enzymes could be classified as transferases, as every hydrolysis
reaction can be regarded as the transfer of a specific chemical group to a water molecule.
However, because of the ubiquity and importance of water in natural processes,
these biocatalysts are classified as hydrolases rather than as transferases.
The term hydrolase is included in every systematic name. The recommendation for the
naming of these enzymes is the formation of a name that includes the name of the substrate
and the suffix -ase. It is understood that the name of a substrate with this suffix
implies a hydrolytic enzyme.
EC 3.1 Acting on ester bonds
The nature of the substrate can differ greatly, as shown in the three examples.
O
49