Production of Se-methylselenocysteine in transgenic plants expressing selenocysteine methyltransferase

BMC Plant Biology

Table 1 Identity and percent composition of Se species in shoot tissue of SMT over-producing A. thaliana line smt2-9.

Se species	Peak #	t_R (min)	m/z	μmol g ^-1 dry weight	% of extractable shoot Se
¹Selenite	nd	nd	nd	0.16	3
²MeSeCys	1	4.75	167 (M+H-NH₃)⁺	0.71	12
²MeSeCys	2	6.25	167 (M+H-NH₃)⁺	1.68	31
²Unidentified	3	8.75	nd	0.27	5
³ γGluMeSeCys	4	7.5	313 (M+H)⁺	1.16	26
³Unidentified	5	10.5	nd	0.37	6
³Unaccounted	-	-	-	-	17

¹Calculated using XAS data. ²Mobile phase water-methanol (99:1, v/v) 0.1% HFBA. ³Mobile phase water-methanol (99:1, v/v) 0.1% TFA. HPLC fractions (0.5 – 1.0 ml) were collected and analyzed for total Se by ICP-MS. Replicate chromatography was also performed using HPLC-ESI-MS to confirm the identity of the compounds in the Se containing peaks. The various Se compounds were quantified based on their Se content. Chromatography and mass spectroscopy data shown in Figure 2.

ISSN: 1471-2229