Ac. Sarmento et al., CARDOSIN-A AND CARDOSIN-B, 2 NEW ENZYMES AVAILABLE FOR PEPTIDE-SYNTHESIS, Journal of molecular catalysis. B, Enzymatic, 5(1-4), 1998, pp. 327-330
Two new aspartic proteases, Cardosins A and B, with a high specificity
toward bonds between hydrophobic amino acids were isolated from the f
lowers of the cardoon, Cynara cardunculus L., and recently characteris
ed [C.J. Fare, A.G.J. Moir, E. Fires, Biotech. Lett., 14(1992) 841.];
[P. Verissimo, C. Fare, A.J.G. Moir, Y. Lin, J. Tang, E. Fires, fur. J
. Biochem., 235 (1996) 762.]. Cardosins were shown to be stable in aqu
eous-organic biphasic systems [M. Barros, M.G.V. Carvalho, F.A. Garcia
, E. Fires, Biotech. Lett. 14 (1992) 174.]. In this work, we have inve
stigated peptide bond specificity of Cardosin A and Cardosin B in what
concerns the amino acids in P'1 position. The results were compared w
ith pepsin under the same conditions. Information about secondary spec
ificity of Cardosin A and B was also investigated by tripeptide synthe
sis. The condensation reactions were carried out in aqueous-organic bi
phasic systems of n-hexane/ethyl acetate and sodium phosphate buffer.
The reaction products were isolated by RF-HPLC and identified by amino
acid analysis and eventually by M.S. The results in the synthesis of
dipeptides showed that Cardosin A and B have similar P'1 position pref
erence. The production of tripeptides by condensation of CBZ . Val . P
he with Phe . OMe, Met . OMe and Val . OMe reveals that the addition o
f Val in the P2 position modifies the Cardosins' preferences concernin
g the amino acid in P'1 position. (C) 1998 Elsevier Science B.V. All r
ights reserved.