Cleavage specificity of cucumisin, a serine protease, with synthetic substrates.
The substrate specificity of a plant serine protease, cucumisin (EC 3.4.21.25), was studied by the use of synthetic oligopeptides and peptidyl-pNA substrates. Since P1'-Ser, Ala, and Gly substrates were hydrolyzed rapidly, cucumisin appears to prefer a small side chain at the P1' position of the oligopeptide substrate. The k(cat)/Km for the hydrolysis of P1-Leu, Ala, Phe, and Glu substrates demonstrated that they were preferentially cleaved over P1-Lys, diaminopropionic acid (Dap), Gly, Val, and Pro substrates. From the digestion of peptidyl-pNAs, the specificity of the protease was determined to be broad, but the preferential cleavage sites were hydrophobic amino acid residues at the P1 position.
Arima
K
K
Department of Chemistry, Faculty of Science, Kagoshima University, Japan.
Yonezawa
H
H
Uchikoba
T
T
Shimada
M
M
Kaneda
M
M
D019662:Cucurbitaceae / Q000201:enzymology*; D004151:Dipeptides / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity
D004151:Dipeptides; D009842:Oligopeptides; D012697:Serine Endopeptidases; C041541:cucumisin