The non-protein ammo acid β-methylamino-L-alanine (BMAA) has been linked to neurodegenerative disease and reported throughout the environment. Proposed mechanisms of bioaccumulation, trophic transfer and chronic toxicity of BMAA rely on the hypothesis of protein misincorporation. Poorly selective methods for BMAA analysis have led to controversy. We recently reported a highly selective method for BMAA quantitation using hydrophilic interaction liquid chromatography-differential mobility spectrometry-tandem mass spectrometry (HILIC-DMS-MS/MS). Here, this methodology is expanded to include protein genic amino acids from hydrolyzed biological samples. For BMAA quantitation, we present a double spiking
isotope dilution approach using D3-BMAA and 13C15N2-BMAA. We apply these methods to study release of BMAA during acid hydrolysis under a variety of conditions, revealing that the majority of BMAA can be extracted along with only a small proportion of protein. A time course hydrolysis of BMAA from mussel tissue was carried out to assess the recovery of BMAA during sample preparation. The majority of BMAA measured by typical methods was released before a significant proportion of protein was hydrolyzed. Little change was observed in protein hydrolysis beyond typical hydrolysis times but the concentration of BMAA increased linearly. These findings demonstrate protein misincorporation is not the predominant form of BMAA in cycad and shellfish.
National Research Council of Canada. Measurement Science and Standards
Beach, Daniel G., Elliott S. Kerrin, Sabrina D. Giddings, Michael A. Quilliam, and Pearse McCarron. ‘Differential Mobility-Mass Spectrometry Double Spike Isotope Dilution Study of Release of β-Methylaminoalanine and Proteinogenic Amino Acids during Biological Sample Hydrolysis’. Scientific Reports 8, no. 1 (8 January 2018). https://doi.org/10.1038/s41598-017-18392-w.