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Table 3 Oxidation of mono-, di- and oligosaccharides by TmXdhA after 24 h with product detection by ESI-Q-TOF-MS in the negative mode

From: Characterization of a novel AA3_1 xylooligosaccharide dehydrogenase from Thermothelomyces myriococcoides CBS 398.93

 

Substrate

Linkage

Oxidation

Substrate

Oxidized product

Degree of oxidation

 

m/z

m/z

%

Monosaccharides

Glucose

 

Y

215

195

 ~ 90

Xylose

 

Y

b

165

b

Mannose

 

Y

215

195

 ~ 90

Galactose

 

Y

215

195

 ~ 90

Disaccharides

Cellobiose

β 1 → 4

Y

377

357

100

Sophorose

β 1 → 2

N

377

 

–

Laminaribiose

β 1 → 3

N

377

 

–

Gentiobiose

β 1 → 6

N

377

 

–

Maltosea

α 1 → 4

Y (Trace)

377

357

 < 5

Kojibiosea

α 1 → 2

N

377

 

–

Nigerosea

α 1 → 3

N

377

 

–

Isomaltosea

α 1 → 6

N

377

 

–

 

Xylobiose

β 1 → 4

Y

317

297

100

Lactose

β 1 → 4

Y

377

357

100

Galactobiose

β 1 → 4

N

377

 

–

Mannobiose

β 1 → 4

Y

377

357

 ~ 50

Glucosyl-mannose

β 1 → 4

Y

377

357

 ~ 90

Chitosanbiose

β 1 → 4

N

375

 

–

Oligosaccharides

Cellotriose

β 1 → 4

Y

539

519

100

Cellotetraose

β 1 → 4

Y

701

681

100

Glucosyl-(1 → 3)-β-D-cellobiose

β 1 → 3/4

Y

539

519

 ~ 80

Xylotriose

β 1 → 4

Y

449

429

100

Xylotetraose

β 1 → 4

Y

581

561

100

Acidic

U4m2X

β 1 → 4;

α 1 → 2

N

471

 

–

U4m2XX

β 1 → 4;

α 1 → 2

Y

603

619, 309

100

C-1 methylated disaccharides

Methylated-cellobiose

β 1 → 4

N

391

 

0

Methylated-lactose

β 1 → 4

N

391

 

0

  1. Detected oxidation is indicated as Y and no oxidation as N. Degree of oxidation was calculated with Eq. 1. All substrates except for 22-(4-O-methyl-α-d-glucuronyl)-xylobiose (U4m2X) and 23-(4-O-methyl-α-d-glucuronyl)-xylotriose (U4m2XX) were detected as chlorine adducts [M + Cl]− while U4m2X and U4m2XX were detected in their anionic form [M–H]− and [M–2H]2−. The degree of oxidation was estimated using Eq. 1 in Material and method section
  2. aCastanospermine included in the reactions
  3. bXylose does not give a clear peak; hence, the percentage was not calculable