Solvent-Tolerant Proteases

15 DISCOVERY AND ENGINEERING OF ENZYMES FOR PEPTIDE SYNTHESIS AND ACTIVATION 

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DMSO Compounds and peptides are commonly dissolved in DMSO as the most universal solvent. HCMV protease is tolerant of DMSO at up to 10% (v/v) with only slight loss in activity. Higher levels of DMSO may be used, and may be compensated for by reducing the level of glycerol in the assay buffer to 10%. 

Mahanta N, Gupta A, Khare SK (2008) Production of protease and lipase by solvent tolerant Pseudomonas aeruginosa PseA in solid-state fermentation using JcUropha curcas seed cake as substrate. Bioresour Technol 99 1729-1735... 

Other benefits may arrive from solvent-resistant bacteria. Ogino et al. isolated Pseudomonas aeruginosa LST-03 whieh ean grow in organic solvents with logPo/w >2.4 and secrets organic solvent-stable lipolytic enzymes. They were able to purify an organic solvent-stable protease which was more stable than the commercially available proteases. Hence, solvent-tolerant strains have become a source for new enzymes. 

The definition of a more efficient enzymatic system could be based on the separation of the catalytic cycle of the enzyme and the degradation step by the Mn3+ reactive species in MnP systems. The Mn3+-chelates present several advantages in their use as oxidants. They are more tolerant to protein denaturing conditions such as extremes of temperature, pH, oxidants, organic solvents, detergents, and proteases, and they are smaller than proteins therefore, they can penetrate microporous barriers inaccessible to proteins. The optimization of the production of the Mn3+-chelate will have to be compatible with the minimal consumption and deactivation of the enzyme. 

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