# Maltose metabolism in serum free CHO culture involves lysosomal acid α-glucosidase

## TL;DR

Chinese hamster ovary cells use maltose as an energy source, and a specific enzyme in lysosomes helps break down maltose into glucose.

## Contribution

This study identifies lysosomal acid α-glucosidase as a key enzyme involved in maltose metabolism in CHO-K1 cells.

## Key findings

- Lysosomal acid α-glucosidase (GAA) is involved in breaking the α(1 → 4)-glycosidic bond in maltose.
- Maltose uptake in GAA-KO CHO-K1 cells is linear up to 40 g/L extracellular maltose.
- Transport of maltose in CHO-K1 cells is concentration-dependent.

## Abstract

Mammalian cells have been previously shown to utilize maltose as an energy source for long-term cell growth. To characterize maltose uptake and consumption in CHO-K1, we measured its intracellular concentrations over time and tracked the incorporation of C13-labelled disaccharides into TCA cycle intermediates. Lysosomal acid α-glucosidase (GAA) was identified to potentially be involved in the initial reaction of breaking the α(1 → 4)-glycosidic bond in maltose, releasing two glucose residues for energy metabolism. Using a GAA-KO CHO-K1 cell line, we showed that GAA is involved in CHO-K1 maltose metabolism. Transport of maltose in wild-type and GAA-KO CHO-K1 is concentration-dependent. The rate of maltose uptake for GAA-KO cells was also linear when extracellular maltose is between 0 to 40 g/L, and saturation in uptake kinetics was not observed over that concentration range.

The online version contains supplementary material available at 10.1038/s41598-025-30901-w.