Thermolysins

Protein-degrading enzymes that are neutral, zinc-dependent, and stable at high heat (EC 3.4.24.4), secreted by the bacterium Bacillus thermoproteolyticus. Thermolysins are the most heat-stable proteinases available commercially, remaining active up to 80 °C, which makes them valuable where proteolysis must occur under hot process conditions. They cleave peptide bonds adjacent to hydrophobic amino-acid residues and serve as model enzymes in protein chemistry as well as industrial biocatalysts — for example, in the enzymatic synthesis of the sweetener aspartame. Their robustness illustrates why thermophilic organisms are rich sources of process-tolerant food enzymes.