Bio-rad Laboratories, Inc.

Technion Research & Development Foundation Ltd

Aran Paulus

Anton Posch

Uri Sivan

Elad Brod

Ning Liu

Steve Freeby

Roumen Bogoev

Kevin McDonald

Camille M Diges

Sricharan Bandhakavi

Annett Hahn-Windgassen

John Walker, Ii

Annett Hanh-Windgassen

Inbal Zafir-Lavie

Katrina Academia

Tim Wehr

John A Walker Ii

Disclosed herein are methods of protein quantification and normalization using haloalkylated tryptophan fluorescence. Complex protein samples, i.e., samples that each contain 1,000 or more distinct proteins, from diverse sources that do not have common protein profiles are treated with a halo-substituted organic compound (i.e. haloalkane) that reacts with tryptophan residues to form fluorescent products. Irradiation of the samples with ultraviolet light and the detection and quantification of the resultant fluorescent emissions from all proteins in each sample are then used to obtain comparative values for total protein content among the various samples. The values thus obtained are found to be valid indications of comparative total protein content, despite the fact that the tryptophan levels vary widely among the various proteins in any single sample and the samples, due to the diversity of their origins, tend to differ among themselves in the identities and relative amounts of the proteins that they contain. Protein samples are also normalized to correct for differences in sample dilution, sample loading, and protein transfer inconsistencies, by using stain-free detection of total protein in each of the samples, or detection of subsamples within each sample.

Stain-free protein quantification and normalization

Methods and devices for purifying, detecting, and collecting analytes fractionated based on pI, separating analytes via electrophoresis and pI, and purifying a target molecule using pI focusing and subsequent crystallization are provided.

Affinity methods and compositions employing electronic control of pH

Apparatuses and methods for controlling ionic strength and/or pH of a solution are provided.

Electronic control of pH and ionic strength

Apparatuses and methods for purifying proteins and other target molecules based on pI are provided.

Electronic protein fractionation

Methods and devices for purification of different cell components from the same sample are provided.

Simultaneous purification of cell components

Phosphorylated peptides are extracted from digests of biological liquids and other peptide mixtures by fractionation on ceramic hydroxyapatite. The ceramic hydroxyapatite is readily usable in a centrifuge, allowing for rapid fractionations of a large number of small volume samples, and accordingly high throughput.

Phosphopeptide enrichment of compositions by fractionation on ceramic hydroxyapatite

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