Table A1.

Product ion data for the microginin type peptides. Masses are given in Dalton rounded to the nearest integer. X₁′ indicates core fragment of Ahda after abstraction of the side chain (m = 58 Da). Leucine and isoleucine cannot be distinguished from the LC-MS/MS data, these amino acids have been deduced from the nearest literary results.

Compound	[M + H]+ m/z	RT min	Amino Acid Sequence	X1-X2-X3-X4	-H2O	X1’-X2-X3-X4	-H2O	X1-X2-X3	-H2O	X1’-X2-X3	-H2O	X1-X2
MG 565	565.5	6.1	Ahda-Thr-Pro-Tyr					384	366	257	239	287
MG 549	549.5	6.2	Ahda-Ala-MePro-Tyr					368	nd	241	nd	257
MG 579	579.6	6.4	MeAhda-Thr-Pro-Tyr					398	380	257	239	301
MG 579	579.6	6.3	Ahda-Thr-MePro-Tyr					398	380	271	253	287
MG 581	581.5	5.5	Ahda-Thr-Pro-OHTyr					384	366	257	239	287
MG 595	595.5	5.7	Ahda-Thr-MePro-OHTyr					398	380	271	253	287
MG FR3	728.6	6.3	Ahda-Thr-Pro-Tyr-Tyr	547	529	420	402	384	366	257	239	287
MG 712	712.6	6.4	Ahda-Ala-MePro-Tyr-Tyr	531	513	404	nd	368	350	241	223	257
MG FR4	742.6	6.6	MeAhda-Thr-Pro-Tyr-Tyr	561	543	420	nd	398	380	257	239	301
MG 744	744.6	6	Ahda-Thr-Pro-OHTyr-Tyr	547	529	nd	nd	384	366	257	239	287
MG 754	754.6	6.7	Ahda-Leu-Pro-Hty-Tyr	573	nd	446	nd	396	nd	269	252	299
MG 607	607.5	6.4	Ahda-Leu-MeVal-Hty					412	394	285	267	299
MG 621	621.6	6.4	MeAhda-Leu-MeVal-Hty					426	408	285	267	313
MG 591	591.5	7.4	MeAhda-Leu-MeVal-Phe					426	408	285	267	313
MG 770	770.6	6.7	Ahda-Leu-MeVal-Hty-Tyr	589	571	462	444	412	394	285	267	299
MG 784	784.6	6.7	MeAhda-Leu-MeVal-Hty-Tyr	603	585	462	nd	426	408	285	267	313
MG 798	798.6	7	Ahda-Leu-MeLeu-Hty-Tyr	617	599	476	458	440	422	299	281	313