Evaluating the effect of glycation on lipase activity using boronate affinity chromatography and mass spectrometry

[Display omitted] •BAC allowed enrichment of glycated proteoforms while maintaining lipase activity.•BAC with MS and activity assays to establish structure–function relationships.•Glycation does not reduce lipase activity and stability. Protein glycation may occur naturally when reducing sugars and proteins coexist, which is often the case for industrial enzymes. The impact of post-translational modifications on enzyme performance (e.g., stability or function) is often not predictable, highlighting the importance of having appropriate analytical methodologies to monitor the influence of glycation on performance. Here, a boronate affinity chromatography method was developed to enrich glycated species followed by mass spectrometry for structural characterization and activity assays for functional assessment. This approach was applied to a (temperature-stressed) lipase used for food applications revealing that storage at -20 °C and 4 °C resulted in minor glycation (below 9%), whereas storage at 25 °C led to a higher glycation level with up to four sugars per lipase molecule. Remarkably, activity measurements revealed that glycation did not reduce lipase activity or stability. Altogether, this novel strategy is a helpful extension to the current analytical toolbox supporting development of enzyme products.