Depletion of human serum albumin in embryo culture media for in vitro fertilization using monolithic columns with immobilized antibodies
Tarasova, I. A., Lobas, A. A., Černigoj, U., Solovyeva, E. M., Mahlberg, B., Ivanov, M. V., Panić-Janković, T., Nagy, Z., Pridatchenko, M. L., Pungor, A., Nemec, B., Vidič, U., Gašperšič, J., Krajnc, N. L., Vidič, J., Gorshkov, M. V. and Mitulović, G. ELECTROPHORESIS. Accepted Author Manuscript. doi:10.1002/elps.201500489.
Affinity depletion of abundant proteins such as human serum albumin (HSA) is an important stage in routine sample preparation prior to tandem mass spectrometry (MS/MS) analysis of biological samples with high range of concentrations. Due to the charge competition effects in electrospray ion source that results in discrimination of the low-abundance species, as well as limited dynamic range of MS/MS, restricted typically by three orders of magnitude, the identification of low-abundance proteins becomes a challenge unless the sample is depleted from high concentration compounds. This dictates a need for developing efficient separation technologies allowing fast and automated protein depletion. In this study we performed evaluation of a novel immunoaffinity-based CIMac depletion column with specificity to HSA (CIMac-αHSA). Because of the convective flow-through channels, the polymethacrylate CIMac monoliths afford flow rate-independent binding capacity and resolution that results in relatively short analysis time compared with traditional chromatographic supports. Seppro IgY14 depletion kit was used as a benchmark to control the results of depletion. Bottom-up proteomic approach followed by label-free quantitation using normalized spectral indexes were employed for protein quantification in G1/G2 and Cleavage/Blastocyst IVF culture media widely utilized in clinics for embryo growth in vitro. The results revealed approximately equal HSA level of 100% ± 25% in albumin-enriched fractions relative to the non-depleted samples for both CIMac-αHSA column and Seppro kit. In the albumin-free fractions concentrated 5.5-fold by volume, serum albumin was identified at the levels of 5 to 30% and 20 to 30% for the CIMac-αHSA and Seppro IgY14 spin columns, respectively.