Table 2.

Absolute quantification of amino-containing metabolites in serum of healthy controls (HC) and gastric cancer (GC) patients^a.

No.	Name	HC (μg/mL)	GC patients (μg/mL)
1	Gln	67.71 ± 19.96	65.13 ± 27.03
2	Glu	67.99 ± 32.11	78.18 ± 37.11
3	His	24.52 ± 5.48	24.95 ± 14.10
4	Thr	40.92 ± 7.17	39.17 ± 19.98
5	Ala	34.36 ± 5.71	35.08 ± 12.20
6	Arg	22.50 ± 6.51	14.39 ± 8.44
7	Tyr	9.18 ± 2.73	7.76 ± 2.44
8	Val	28.13 ± 6.26	30.15 ± 13.34
9	Trp	17.03 ± 2.40	11.57 ± 3.04
10	Ile	10.89 ± 2.57	12.44 ± 6.68
11	Leu	19.29 ± 4.72	18.78 ± 6.56
12	Phe	18.86 ± 4.04	24.37 ± 12.95
13	Asp	8.52 ± 2.95	9.22 ± 7.76
14	Asn	5.07 ± 1.06	4.69 ± 2.24
15	Ser	32.15 ± 4.73	35.68 ± 17.64
16	Gly	139.47 ± 16.83	124.99 ± 49.29
17	Met	3.86 ± 0.74	5.58 ± 5.26
18	Lys	16.66 ± 5.53	14.03 ± 6.62
19	Cys	6.33 ± 0.45	5.79 ± 0.51
20	NMTYA	0.00044 ± 0.000079	0.00041 ± 0.000042
21	TRA	0.097 ± 0.01	0.12 ± 0.031
22	NMTRA	0.00041 ± 0.00023	0.00056 ± 0.00053
23	5-HT	0.62 ± 0.04	0.44 ± 0.05

Gln: glutamine; Glu: glutamic acid; His: histidine; Thr: threonine; Ala: alanine; Arg: arginine; Tyr: tyrosine; Val: valine; Trp: tryptophan; Ile: isoleucine; Leu: leucine; Phe: phenylalanine; Asp: aspartic acid; Asn: asparagine; Ser: serine; Gly: glycine; Met: methionine; Lys: lysine; Cys: cysteine; NMTYA: N-methyltyramine; TRA: tryptamine; NMTRA: 3-(2-methylaminoethyl) indole; 5-HT: serotonin.

^aData were shown as average ± standard deviation.