Protein testing

Methods for detecting the A1 and A2 beta-casein variants directly in a milk sample.

Common methods

Mass spectrometry (MALDI-TOF, ESI-MS, LC-MS/MS). Detects A1 and A2 with high specificity and sensitivity; can resolve all genetic variants of beta-casein in a single run.
HPLC and FPLC. Reverse-phase chromatography separates A1 and A2 by hydrophobicity. Capillary electrophoresis offers similar resolution at lower sample volumes.
Gel-based methods. Urea-PAGE and isoelectric focusing can distinguish A1 and A2 but are less suited to quantification.

Detailed studies on each method are linked from the research library.