Industrial Biotransformations

a-Glucosyl transferase
Protaminobacter rubrum
OH
1) Reaction conditions
pH: 5.8
T: 40 oC medium: aqueous
reaction type: isomerization
catalyst: immobilized, whole cells
enzyme: Sucrose glucosylmutase (isomaltulose synthetase, sucrose α-glucosyltransferase)
strain: Protaminobacter rubrum
CAS (enzyme): [159940–49–5]
2) Remarks
CH 2OH
OH
O
OH
O
CH2OH
O
HO
OH
CH 2OH
1 = sucrose, saccharose
2 = palatinose, isomaltulose,
6-O-α-D-glucopyranosyl-D-fructofuranose
Fig. 5.4.99.11 – 1
● Palatinose, a reducing disaccharide, occurs naturally in low amounts in honey and sugar-cane
extract.
● The word palatinose is derived from palatin, the Latin name for the Pfalz region in Germany.
● α-Glucosyltransferase simultaneously produces isomaltulose and smaller amounts of trehalulose
(1-O-α-d-glucopyranosyl-β-d-fructose) from sucrose.
● Palatinose (isomaltulose) is the kinetically preferred product, while trehalulose is the thermodynamically
preferred product.
● The commercial product contains about 5 % water.
512
OH
CH 2OH
1 2
OH
O
OH
O
CH 2
(α-1,2 bond) (α-1,6 bond)
OH
O
EC 5.4.99.11
HO
OH
CH2OH