Screening for non-protein amino acids in seeds of the Guam cycad, Cycas circinalis, by an improved GC-MS method.
The non-protein amino acid, beta-N-methyl-amino-L-alanine (L-BMAA) from Cycas circinalis seeds, has been implicated as a causative agent of amyotrophic lateral sclerosis-Parkinsonism dementia complex (ALS-PDC), a disease known from Guam and other areas in the western Pacific. We analyzed C. circinalis seeds for additional free non-protein amino acids by a recently developed GC-MS method. The samples were prepared by water extraction of seed flour. The amino acids present in the extract were derivatized by N(O,S)-isobutyloxycarbonylation of the amine functional groups and then tert-butyldimethylsilylation of the carboxyl functional groups. Peaks for a total of seventeen derivatives of non-protein amino acids were detected by GC-MS. In addition to L-BMAA, four other non-protein amino acids were identified as beta-alanine, gamma-amino-butyric acid, pyroglutamic acid, and alpha-aminoadipic acid.
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C H
CH
Department of Botany, University of Texas, Austin 78713-7640.
Brownson
D M
DM
Mabry
T J
TJ
D000596:Amino Acids / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006141:Guam; D010944:Plants / Q000737:chemistry; D012639:Seeds / Q000737:chemistry*
D000596:Amino Acids