Rand Protease: The Role of Calcium-Binding Site on Stability with Mutagenesis and The Effectiveness on Leather Dehairing

The study focused on the stability of Rand protease, a thermostable enzyme from Bacillus subtilis, and its application in leather dehairing. Key calcium-binding sites, Leu75 and Tyr171, were identified as critical for the enzyme's stability through in silico mutagenesis. The mutation of Leu75 to alanine significantly decreased stability. The enzyme was effective in dehairing leather, producing higher quality leather with smaller pores and softer texture compared to chemical treatments, especially at pH 7.0 over 18 hours without additional metal ions. However, the addition of zinc improved epidermis removal. The study suggests that Rand protease could replace traditional lime sulfite methods in leather processing and highlights the importance of Leu75 and Tyr171 for enzyme stability, with future research needed to refine the protease's 3D structure and improve its practical applications.