Protease substrates with P1 aromatic or positively charged residues

Protease substrates with P1 aromatic or positively charged residues refers to a broad classification of peptide sequences defined by the amino acid located at the P1 position, which is the residue immediately N-terminal to the scissile bond. This nomenclature, established by Schechter and Berger, identifies the primary determinant for the specificity of proteases as they bind to the enzyme's S1 pocket (Schechter & Berger, 1967). Substrates with P1 aromatic residues, such as Phenylalanine or Tyrosine, are typically cleaved by chymotrypsin-like serine proteases, which are involved in processes like digestion and the activation of inflammatory mediators (Hedstrom, 2002). Conversely, substrates with P1 positively charged residues, such as Arginine or Lysine, are the primary targets for trypsin-like proteases, which are essential for the blood coagulation cascade and the complement system (Rawlings et al., 2018). This term does not describe a single therapeutic target but rather a functional category of molecules used to characterize the activity of various enzymes. In clinical practice, pharmacological agents are designed to inhibit the specific proteases that act on these substrates—such as Thrombin or Factor Xa—to treat conditions like deep vein thrombosis or stroke.

Other names

P1-aromatic protease substratesP1-basic protease substratesTrypsin-like protease substratesChymotrypsin-like protease substratesS1-pocket specific substrates

Drugs typically target the proteases (e.g., Thrombin, Factor Xa, or the Proteasome) that recognize these specific P1 residues, inhibiting their catalytic activity to prevent the cleavage of physiological substrates.