Method for enhanced accuracy in predicting peptides using liquid separations or chromatography
A method for predicting the elution time of a peptide in chromatographic and electrophoretic separations by first providing a data set of known elution times of known peptides, then creating a plurality of vectors, each vector having a plurality of dimensions, and each dimension representing the elution time of amino acids present in each of these known peptides from the data set. The elution time of any protein is then be predicted by first creating a vector by assigning dimensional values for the elution time of amino acids of at least one hypothetical peptide and then calculating a predicted elution time for the vector by performing a multivariate regression of the dimensional values of the hypothetical peptide using the dimensional values of the known peptides. Preferably, the multivariate regression is accomplished by the use of an artificial neural network and the elution times are first normalized using a transfer function.
1. A method for predicting the elution time of peptides in liquid separations comprising the steps of:
a. providing a data set of known elution times of known peptides,
b. creating a plurality of vectors, each vector having twenty dimensions, each dimension representing an amino acid potentially present in each of said known peptides, and each vector associated with the elution time of said peptide,
c. creating a hypothetical vector by assigning dimensional values for at least one hypothetical peptide, and
d. calculating a predicted elution time for said hypothetical vector by performing at least one multivariate regression fitting said hypothetical peptide to said plurality of vectors.
2. The method of claim 1 comprising the further step of normalizing the known elution times prior to creating said plurality of vectors.
3. The method of claim 1 wherein the multivariate regression is performed using an artificial neural network.
4. The method of claim 3 wherein the artificial neural network trained with a method selected from the group consisting of gradient descent algorithms and conjugate gradient algorithms.
5. The method of claim 4 wherein the artificial neural network trained with a gradient descent algorithm selected from the group consisting of a backpropagation algorithm and a quickprop algorithm.
6. The method of claim 2 wherein normalization is performed by optimizing a function using multiple regressions.
7. The method of claim 6 wherein the multiple regressions are calculated using a genetic algorithm.
8. The method of claim 6 wherein the function is selected from the group consisting of linear and non-linear functions.
9. The method of claim 1 wherein the liquid separation is performed by a method selected from the group consisting of liquid chromatography, both standard and reverse phase, electrophoretic separations, capillary electrophoresis; field flow fractionation, and combinations thereof.