Proteins are present in wine. The most common proteins include thaumatin-like proteins and chitinases and have a role in the formation of turbidity (haze) especially visible in white wine. The quantity of haze forming is dependent on the quantity of phenolics in the wine. Some of those proteins are considered nuisance. Some of them are grape pathogenesis-related proteins. Those proteins have been identified by mass spectrometry and originate from grape, yeast, bacteria and fungi.