Table 4.

Electrospray ionization collision-induced dissociation tandem mass spectrometry fragment ions observed for [Asp³] MC-FA, MC-FA, [Asp³] MC-WA and MC-WA.

Fragment Assignment a	[Asp3] MC-FA (18)	MC-FA (19)	[Asp3] MC-WA (20)	MC-WA (21)
M + H	930	944	969	983
M − H2O + H	912	926	951	965
M − Mdha − H2O + H	829	843	868	882
M − Adda sidechain + H	796	810	835	849
M − Adda sidechain − H2O + H	778	792	817	831
M − Adda + H	617	631	656	670
M − Adda − H2O + H	599	613	638	652
Adda-Glu-Mdha-Ala-X-(Me)Asp − NH3 + H	842	856	881	895
Adda-Glu-Mdha-Ala-X − NH3 + H	727	727	766	766
Adda-Glu-Mdha-Ala − NH3 + H	580	580	580	580
Adda-Glu-Mdha − NH3 + H	509	509	509	509
Adda′-Glu-Mdha-Ala-X + H	593	593	632	632
Adda′-Glu-Mdha-Ala + H	446	446	446	446
Adda′-Glu-Mdha + H	375	375	375	375
Mdha-Ala-X-(Me)Asp-Ala + NH4	505	519		558
Ala-X-(Me)Asp-Ala + NH4	422	436	461	475
X-(Me)Asp-Ala + NH4	351	365	390	404
Mdha-Ala-X-(Me)Asp-Ala + H	334	502	527	541
Ala-X-(Me)Asp-Ala + H	405	419	444	458
X-(Me)Asp-Ala + H	488	348	373	387

^a X = Position two amino acid (for 18–19 = 147 Da and 20–21 = 186 Da); Adda′ = Adda minus NH₂ and the sidechain (C₉H₁₁O).