Table 2. Specific activity and hydrolysis/transglycosylation ratio of wild-type GTFO-∆N and GTFA-∆N enzymes, and of GTFO-derived mutants, at 100 mM sucrose, and methylation, 1H NMR and pullulanase digestion analysis of the polysaccharides produced.
Enzyme | Activitya (U/mg) | Hydrolysis/trans-glycosylation (%) | Chemical shiftc(%) |
Methylation analysisb(%) |
Maltosed | ||||
---|---|---|---|---|---|---|---|---|---|
(α1 → 6) | (α1 → 4) | Glcp(1 → | → 4)Glcp(1 → | →6)Glcp(1→ | →4,6)Glcp(1→ | ||||
GTFA-ΔN | 22.7 ± 1.8 | 9/91 | 42 | 58 | 13 | 45 | 27 | 15 | 45.9 ± 2.2 |
GTFO-ΔN | 13.7 ± 0.9 | 43/57 | 21 | 79 | 11 | 69 | 9 | 11 | 8.7 ± 1.3 |
GTFO-ΔN A977Q | 14.4 ± 1.2 | 35/65 | 31 | 69 | 16 | 51 | 18 | 15 | 24.9 ± 3.2 |
GTFO-ΔN lp977 | 1.5 ± 0.3 | 35/65 | 33 | 67 | 14 | 53 | 18 | 15 | 25.5 ± 2.0 |
GTFO-ΔN SS-HA | 11.0 ± 1.5 | 44/56 | 24 | 76 | 12 | 68 | 10 | 10 | 8.3 ± 1.0 |
GTFO-ΔN α4 | 13.3 ± 2.6 | 37/63 | 36 | 64 | 19 | 43 | 21 | 18 | 28.1 ± 2.4 |
GTFO-ΔN A977Q/α4 | 12.2 ± 1.2 | 33/67 | 39 | 61 | 18 | 42 | 22 | 18 | 35.8 ± 3.0 |
GTFO-ΔN lp977/α4 | 1.2 ± 0.3 | 30/70 | 40 | 60 | 17 | 44 | 22 | 17 | 31.6 ± 3.1 |
GTFO-ΔN SS-HA/α4 | 13.4 ± 0.9 | 37/63 | 36 | 64 | 16 | 45 | 22 | 17 | 29.1 ± 3.5 |
GTFO-ΔN lp977/SS-HA | 0.3 ± 0.08 | 36/64 | 31 | 69 | 13 | 56 | 19 | 12 | 27.0 ± 3.3 |
GTFO-ΔN lp977/SS-HA/α4 | 1.9 ± 0.4 | 30/70 | 40 | 60 | 17 | 44 | 23 | 16 | 34.1 ± 2.8 |
GTFO-ΔN A977Q/SS-HA/α4 | 15.8 ± 2.2 | 31/69 | 39 | 61 | 15 | 45 | 23 | 17 | 35.4 ± 3.6 |
GTFO-ΔN A977Q/V1083D | 17.7 ± 1.5 | 34/66 | 36 | 64 | 18 | 42 | 22 | 18 | 28.8 ± 2.5 |
GTFO-ΔN A977Q/G1087N | 29.0 ± 3.0 | 31/69 | 34 | 66 | 16 | 47 | 20 | 17 | 25.2 ± 2.1 |
GTFO-ΔN A977Q/V1083D/G1087N | 21.9 ± 1.2 | 30/70 | 38 | 62 | 17 | 42 | 22 | 19 | 30.3 ± 2.8 |
aActivity measured at 100 mM sucrose at 35 °C. bThe ratios of the different glucosyl substitutions are shown in molar percentage based on the intensities from GLC. cThe ratios of integration of the surface areas of the (α1 → 6) linkage signal at 4.96 ppm and the (α1 → 4) linkage signal at 5.36 ppm in the 1H NMR spectra are displayed. dThe percentage of maltose in the pullulanase M1 digestion product mixtures of polysaccharides produced by the respective enzymes based on the glucosyl unit.