Industrial Biotransformations

Transaminase
Bacillus megaterium
1) Reaction conditions
[2]: 0.7 M, 61.7 g · L –1 [88.11 g · mol –1 ]
medium: aqueous
reaction type: amino group transfer
catalyst: suspended whole cells
enzyme: aminotransferase (transaminase)
strain: Bacillus megaterium
2) Remarks
O
1 = 1-methoxy-propan-2-one
2 = isopropylamine
3 = methoxy isopropylamine
4 = acetone
Fig. 2.6.1.X – 1
● Isopropylamine is the choice for the amino donor because it is a cheap and a kinetically attractive
molecule.
● Main disadvantage of the wild-type transaminase is that the conversion is limited due to product
inhibition.
● Starting with the wild-type transaminase, the gene encoding the enzyme could be optimized
step by step by mutation.
● A single mutation in the gene coding the transaminase increases the possible product concentration
from 0.16 M to 0.45 M.
● The screening criteria for better genes included, beside higher inhibitor concentrations, better
reaction rates, higher stability and lower K M-values.
● Since no recycling of the catalyst is integrated, the residual activity after one batch run is of no
interest.
3) Flow scheme
Not published.
E
O NH2 NH2 + O
+
1 (R/S)-2 (S)-3 4
O
EC 2.6.1.X
Celgene Corporation
271