Determination and prediction of peptide mobilities by micellar electro-kinetic chromatography using adaptive neuro-fuzzy inference system as a feature selection method

Mobility of 128 peptides composed of up to 14 amino acids is determined for sodium dodecyl sulfate (SDS) micellar systems using micellar electrokinetic chromatography (MEKC). The mobilities of these peptides are predicted using back propagation of error artificial neural networks (BP-ANNs). Adaptive neuro-fuzzy inference system (ANFIS) which can deal with linear and nonlinear phenomena is used to select the inputs of BP-ANN. A 3:4:1 BP-ANN model with four variables of Kappa substituent constant, Kappa(H), number of peptide bonds, (ln(N), molar refractivity of C-terminal, MRC, and steric effects at N-terminal, ES,N, which incorporate substituent, steric and molar refractivity effects as its inputs was developed. Comparison of Multiple Linear Regression (MLR) and ANN results shows the nonlinear characteristic of the phenomena. The nonlinear model was successful in predicting the mobilities of 120 peptides except for the ones (8 peptides) with negatively charged amino acids.

Exploring Cinnamic Acid Multitarget Hybrids in Terms of 2D-QSAR

Cinnamic acids hybrids present a variety of significant biological activities and are characterized as pleiotropic agents. The 2D- QSAR analysis presented here attempts to identify the structural features and physicochemical properties of cinnamic acids hybrids presenting: a) antitumor activity; b) immunosuppressive activity; c) inhibitory activity on various enzymes; d) antioxidant activity. A 2D-QSAR analysis was carried out for 26 data sets of compounds taken from the literature using the C-QSAR program of Biobyte. In 5 cases hydrophobicity appeared to be important. Steric factors in the form of overall molar refractivity (CMR), molar refractivity of the substituents (MR), molar volume (MgVol) and the Verloop Sterimol parameters have a significant impact on the biological activity whereas electronic parameters as Hammett σp, σm, σo or Σσ appear in most of the cases. The anticancer as well as anti-inflammatory and antioxidant activities of caffeic acid hybrids are governed by lipophilicity, electron and stereochemical factors.