Characterization of chitinase isoforms from grape juice

Abstract

Grape chitinases are recognized as being mainly responsible for protein haze formation in white wines. Vitis vinifera L. cv. Manzoni Bianco grape juice proteins were fractionated using anion exchange and hydrophobic interaction chromatographies. According to SDSPAGE and zymography, six protein bands with chitinolytic activity were subjected to mass spectrometry (MALDI-TOF/TOF MS), which assigned all the bands to Vitis vinifera class IV chitinases. These grape chitinase isoforms showing different electrophoretic and chromatographic behaviours are likely to be also distinct in their functionality in wine. This could be relevant to understand the involvement of single chitinase components in wine hazing and to develop specific winemaking techniques for their removal from wine