Proteases peptide bond breakage

Mechanistically, it was first proposed that the enzyme—metal—substrate (EMS) complex involved first-sphere coordination of substrate to enzyme-bound metal ion. For transition metal ions, 3d orbitals were suggested to facilitate catalysis by promoting delocalization of electrons in the substrate, thereby aiding bond lengthening and breakage, especially for proteases catalyzing peptide bond cleavage . For phosphate transfer enzymes, a transition between rr-levels in the donor-acceptor (substrate-metal) was proposed as the mechanistic role for metal in catalysis . 

Linkage specificity An enzyme that catalyzes the formation or breakage of only certain bonds in a molecule has linkage specificity. Proteases, such as trypsin, chymotrypsin, and elastase, are enzymes that selectively hydrolyse peptide bonds. Thus these enzymes are linkage specific. 

Enzymatic peptide synthesis can proceed by two mechanisms thermodynamic and kinetic control (Kumar and Bhalla 2005). The thermodynamically controlled synthesis of peptides (TCS) with proteases represents the reverse of the hydrolytic breakage of peptide bond catalyzed by those enzymes, as shown in the scheme (Jakubke et al. 1985) ... 

---

See also in sourсe #XX -- [ ]

---