# Characterization and Monitoring of Isomalto/Malto-Polysaccharide Formation by Different 4,6-α-Glucanotransferases

## TL;DR

This study explores how different enzymes convert starch into specific polysaccharides, revealing insights into the structure and formation process.

## Contribution

The study provides detailed insights into enzyme-dependent differences in isomalto/malto-polysaccharide formation and synthesis mechanisms.

## Key findings

- 1H NMR spectroscopy showed minimal impact of pH and temperature on product composition.
- Enzymatic fingerprinting revealed enzyme-dependent differences in the length distribution of 1,6-linked sections.
- Larger oligosaccharides and branched malto-oligosaccharides are utilized during IMMP synthesis.

## Abstract

GtfB type I enzymes, a subfamily of 4,6-α-glucanotransferases,
are enzymes which convert starch into isomalto/malto-polysaccharides
(IMMPs) by synthesizing α-1,6-linked chains. The structure of
IMMPs highly depends on the enzyme and the substrate used. In this
study, the IMMP formation of eight GtfB type I enzymes was investigated
in detail by using different substrates and conditions. 1H NMR spectroscopy was used to analyze the structural composition
(including the portion of released glucose) and revealed little impact
of pH and temperature on the product composition for the investigated
enzymes. However, enzymatic fingerprinting analysis revealed enzyme-dependent
differences in the length distribution of the 1,6-linked sections
of the IMMPs. A detailed reaction monitoring by HPAEC-PAD and NMR
spectroscopy showed that larger oligosaccharides are initially used
for IMMP synthesis and that branched malto-oligosaccharides are also
converted. Overall, detailed information on the reaction time course
and the structural composition of the products were obtained.