Quantitative structure--activity relationships of the synthetic substrates for elastase enzyme using nonlinear partial least squares regression.

Eighty-nine synthetic substrates for elastase enzyme and its activities (log 1/Km, log kcat, and log Kcat/Km) are treated using partial least squares (PLS) and quadratic partial least squares (QPLS). Chemical features of synthetic substrates are described using principal properties (PPs). By using the QPLS method, we obtain the nonlinear model equations for three properties (log 1/Km, log kcat, and log kcat/km) with the correlation coefficient 0.736, 0.918, and 0.868, respectively. Also, the predictive correlation coefficients for these model equations are 0.640, 0.865, and 0.793, respectively. By this study, it becomes clear that the z2 value of the amino acid residue on position A and the size of the side chain for amino acid residues on position B are related to the properties of the synthetic substrates.