Table 1:

Description of the main MM peaks. The data presented are mainly extracted from references^{4,6,8,29,34,39,51,66,70,72}

Recommended nomenclature	Previous nomenclature	ppma	Cross-peaks in 2D spectrab	J, Hzc	Tentative Assignment	Observations
M0.94	M1	0.94 0.88	0.94, 2.05	7.7(d)	Leucine, isoleucine, valine	-reported in vivo at all magnetic fields -two main peaks4,29,66,72
M1.22	M2	1.22	1.22, 4.20	6.6(d)	Threonine	-reported in vivo starting at 3 T28,71,81
M1.43	M3	1.43	1.43, 1.70 1.43, 4.32	7.7(d)	Alanine	-reported in vivo at all magnetic fields
M1.70	M4	1.70	1.70, 1.43 1.70, 3.00	m 7.8(t)	Lysine, arginine, leucine	-reported in vivo starting at 3 T28,71,81 -scalar coupling between M1.70-M3.00 is important for the detection of GABA
M1.81	-	1.81	-	-	To be confirmed in future studies	-reported in vivo in rat brain at 17.2 T29. This peak was identified based on a parameterization of the in vivo acquired MM signal using 32 individual Gaussian functions, therefore its biological relevance needs to be confirmed
M1.9	-	1.9	1.89, 2.03	-	To be confirmed in future studies	-reported in vivo in rat brain at 9.4 T66 and 17.2 T29. Several peaks were identified based on a parameterization of the in vivo acquired MM signal using 15 or 32 individual Gaussian functions, therefore their biological relevance needs to be confirmed
M2.05	M5 (M5a66) (M5b66)	2.05 2.00 2.03	2.05, 0.94 2.03, 1.89 2.07, 3.22	m	Glutamate, glutamine,	-reported in vivo at all magnetic fields
M2.07	-	2.05, 2.07, 2.11	None4,8	s	To be confirmed in future studies	-peak reported in ref4,8 -peak considered to belong to the MM group M5 in ref4,8
M2.17	(M5c66)	2.17	2.16, 2.54 2.17, 3.80	-	To be confirmed in future studies	-peak reported in ref4,8,29,66,72 and considered to belong to the MM group M5 -reported in vivo starting at 9.4 T in rat brain
M2.27	M6 (M6a)66 (M6b)66	2.27	-	8.2(m)	Glutamate, glutamine	-reported in vivo starting at 3 T28,71,81
M2.37		2.37	-	-	To be confirmed in future studies	-reported in vivo in rat brain at 9.4 T66, 16.4 T72 and 17.2 T29. Identified based on a parameterization of the in vivo acquired MM signal using 15, 17 or 32 individual Gaussian functions, therefore their biological relevance needs to be confirmed. This resonance might also be caused by the effect of field on strongly coupled methylenes of glutamate/glutamine
M2.50	(M6c)66	2.50	-	-	To be confirmed in future studies	-reported in vivo in rat brain at 9.4 T66 and 17.2 T29. Identified based on a parameterization of the in vivo acquired MM signal using 15 or 32 individual Gaussian functions, therefore their biological relevance needs to be confirmed.
M2.54	(M6d66) (M739)	2.54 2.57	2.54, 2.16 2.55, 2.74	~10,18(dd)	β-methylene protons of aspartyl groups	-reported in vivo starting at 3 T71 and assigned to β-methylene protons of aspartyl groups at 9.4T39
M2.74	(M839) (M6e66)	2.74 2.68	2.74, 2.55	~4,18(dd)	β-methylene protons of aspartyl groups	-reported in vivo starting at 9.4 T and assigned to β-methylene protons of aspartyl groups in ref39
M2.97	-	2.97	-	-	To be confirmed in future studies	-reported in vivo in rat brain at 9.4 T66 and 17.2 T29. Identified based on a parameterization of the in vivo acquired MM signal using 15 or 32 individual Gaussian functions, therefore their biological relevance needs to be confirmed.
M3.00	M7 (M939) (M7a66) (M7b66)	3.00 3.01 2.96 3.04	3.00, 1.70 3.00, 3.31	7.6(t)	Lysine, (Cys)2	-reported in vivo at all magnetic fields
M3.21	M8a66 (MM851) (M1039) M8b66	3.21 3.21 3.21 3.26	3.22, 2.07	-	Valine-Hβ4 αCH protons of protein amino acids39	-reported in vivo starting at 3 T28,71,81 -phosphatidyl choline methyl (singlet) may contribute
M3.43 – 3.95	M966 —29	3.43 – 3.95 3.54 – 3.95		-	To be confirmed in future studies	-reported in vivo in rat brain at 9.4 T66 and 17.2 T29. Identified based on a parameterization of the in vivo MM signal using 15 or 32 individual Gaussian functions, therefore their biological relevance needs to be confirmed.
M3.71	(M1139)	3.71		-	αCH protons of protein amino acids	-reported in vivo starting at 3 T28,71,81 with improved spectral resolution at 7 T
M3.79	M1239 MM951	3.79 3.77	3.80, 2.17 3.80, 4.91	-	αCH protons of protein amino acids	-reported in vivo starting at 3 T28,71,81 with improved spectral resolution at 7 T
M3.87	M1339	3.87		-	αCH protons of protein amino acids	-reported in vivo starting at 7 T-9.4 T
M3.97	M1439	3.97		-	αCH protons of protein amino acids	-reported in vivo starting at 3 T28,71,81 with improved spectral resolution at 7 T
M4.05–4.43	—29 M1066	4.05 – 4.42 4.22 – 4.43	4.24,1.24 4.32, 1.43		Threonine-Hβ4,8 Threonine-Hγ4,8
M4.20	M1539	4.20		-	αCH protons of protein amino acids	-reported in vivo starting at 7 T-9.4 T -at 9.4T and higher several MM peaks were reported in this range, care has to be taken regarding the water suppression in this range

^aSmall variations in ppm (~0.01–0.04 ppm) can be found in different papers.

^bCross-peak chemical shifts may differ by +0.02 ppm between rat⁴ and human⁸ brain studies.

^cCoupling constants (J, Hz) and multiplicities (s-singlet, d-doublet, t-triplet, m-multiplet, dd-double doublet) were determined from 2D J-resolved ¹H NMR spectra and published in references ^4,8. Small variations in Hz (~0.04Hz) can also be noticed in different papers.