Table 2. Differential metabolites identified by LC-MS secondary mass spectrometry.

Metabolin	Type	Mass	RT.s	vip	p corr	p value	fold_change
Glutathione	[M + H]+	307.1	57.5	8.4	−0.91	2.74E-06	−1.03
cGMP	[M − H]−	345.0	58.0	1.4	−0.89	5.71E-04	−0.86
5-phosphoribosyl-1-diphosphate	[M − H]−	390.0	35.1	2.6	−0.85	2.40E-03	−0.62
dTMP	[M − H]−	322.1	70.4	2.0	0.88	8.13E-04	0.70
Cysteine	[M + H]+	121.0	59.1	2.2	0.88	1.16E-08	0.94
Adenine	[M + H]+	135.1	195.9	3.2	0.89	1.07E-05	1.01
2-Chloroadenosine	[M + H]+	301.1	409.6	5.5	0.81	1.58E-06	1.07
Xanthine	[M + H]+	152.0	75.5	3.0	0.90	3.31E-06	1.10
Uridine 5-diphosphoglucuronic acid	[M − H]−	580.0	48.5	1.6	0.92	9.11E-04	1.19
Xanthosine	[M + H]+	284.1	171.4	1.3	0.89	5.76E-09	1.22
Uridine monophosphate (UMP)	[M − H]−	324.0	46.4	10.4	0.98	2.62E-06	1.32
Adenylosuccinate	[M − H]−	463.1	126.0	15.3	0.96	1.07E-04	1.35

Type, ionization mode; [M + H]+, positive ion mode; [M − H]−, negative ion mode; Mass, exact molecular weight; RT.s, retention time/second; vip, PLS-DA first principal component variable importance in projection; pvalue, t-test significance; Pcorr, p (corr) value of S-plot correlation; fold_change, logarithm of Per-KD/WT fold change (fold change >0 means WT > Per-KD; fold change <0 means WT < Per-KD). All the metabolites listed here did MS/MS.