Alkaline proteases break down the proteins in the substances that  "cement" the hair root. That loosens the hair which can then be degraded by chemical action. 

The main goal of unhairing and liming is to loosen and remove hair and epidermis. The process removes non-collagen substances​ and opens up the fiber structure. The structure's complexity can lead to process challenges. That can result in inadequate loosening of hair, enlarged bellies and/or loose grain and wrinkles. 

Unhairing & liming involves the use of lime and sodium sulfide. These are used in combination with liming auxiliaries such as sharpening agents and tensides. Modern processes also use readily biodegradable proteases. The complex raw material structure needs very specific alkaline proteases. These function as liming agents to speed up the reactions of the chemicals used. They also allow tanneries to reduce their chemical usage. 

“Cementing substances”  surround the basement membrane of the hair root. These substances include proteins like proteoglycans, glycosaminoglycans and dermatan sulfate.  Proteins consist of polypeptide chains of amino acids linked by peptide bonds. Proteases break down these bonds. In that way, proteases help remove the cementing proteins that surround the hair root. Proteases first loosen the hair, then chemical action degrades it.  

Combining alkaline proteases with alkaline lipases in unhairing & liming boosts the benefits. Lipases break down fats and oils. Proteases break down the membranes that surround fat cells. So proteases make the fat accessible to the lipase. This synergistic action improves fat dispersion.  Together, alkaline proteases and lipases deliver excellent hair and scud loosening. The result is​ a clean and relaxed pelt that is ready for the next step. Tanneries can add alkaline lipases and proteases at the early stage of unhairing. Alternatively, they can add them in hair burning, hair-saving, or at the end in the reliming process.