In a cell or tissue, metabolic pathways are enzyme-mediated biochemical processes that result in the biosynthesis (anabolism) or catabolism) of natural product small molecules. Enzymes catalyze the transformation of substrates into structurally related products in each pathway. Although macromolecular processes like DNA replication and repair as well as protein synthesis and degradation are also a part of metabolic processes, small molecules are typically transformed during these processes. The process of metabolism keeps the cells and organism alive. It has been reported that metabolic activity imbalances play a significant role in a number of pathologies, including cancer, inflammatory diseases, cardiovascular diseases, and neurodegenerative illnesses.
Proteases (peptidases) are enzymes that hydrolyze peptide bonds in proteins. Exopeptidases cleave a terminal amino acid residue at the end of a polypeptide; endopeptidases cleave internal peptide bonds. Proteases can be classified based on the chemical groups that function in catalysis. Cysteine, serine, threonine, glutamic acid, aspartate proteases, and matrix metalloproteases are the six categories into which proteases can be divided. Proteases can shed various transmembrane proteins, as is the case with metalloproteases and cysteine proteases, or they can convert receptor agonists into antagonists and vice versa, as is the case with the conversion of chemokines by metalloproteases, dipeptidyl peptin, and numerous repair proteins during apoptosis. Proteases can also activate proteins such as cytokines or inactivate them, such as numerous repair proteins Many proteases contain a large number of additional domains or modules in addition to the catalytic domains, greatly increasing the complexity of their functions.
Proteases are ubiquitous in biosystems where they have diverse roles in the biochemical, physiological, and regulatory aspects of cells and organisms. Proteases represent the largest segment of the industrial enzyme market where they are used in detergents, in food processing, in leather and fabric upgrading, as catalysts in organic synthesis, and as therapeutics. Microbial protease overproducing strains have been developed by conventional screening, mutation/selection strategies and genetic engineering, and wholly new enzymes, with altered specificity or stability, have been designed through techniques such as site-directed mutagenesis and directed evolution.