Table 5.

Percentage of lactate isotopomers and isotopologues (mean ± SD, n = 12) generated by 4T1, traced by [1,2-¹³C₂]-, [1-¹³C]-, [6-¹³C]- and [1,2,3-¹³C₃]glucose before and after calibration.

		Lactate derived from glycolysis		Ratio of lactate derived from glucose carbon 1,2,3 over that derived from glucose carbon 4,5,6
		Glc carbon 1,2,3	Glc carbon 4,5,6
[1,2- 13 C 2 ]glucose	Before calibration	56% ± 0.43%	34% ± 0.41%	1.6
	After calibration	47% ± 0.47%	42% ± 0.80%	1.1
[1- 13 C]glucose	Before calibration	49% ± 0.45%	37% ± 0.36%	1.3
	After calibration	45% ± 0.44%	41% ± 0.36%	1.1
[6- 13 C]glucose	Before calibration	40% ± 0.55%	47% ± 0.50%	0.85
	After calibration	44% ± 0.56%	43% ± 0.50%	1.0
[1,2,3- 13 C 3 ]glucose	Before calibration	54% ± 0.38%	34% ± 0.33%	1.6
	After calibration	46% ± 0.38%	41% ± 0.36%	1.1

Percentage of lactate isotopomers and isotopologues derived from [1,2-¹³C₂]glucose is calibrated using 1.5 ([2,3-¹³C₂]lactate VS lactate, the right panel of Fig. 5A). Percentage of ¹³C-labeling lactate derived from [1-¹³C]glucose and [6-¹³C]glucose is calibrated using 1.2 ([3-¹³C]lactate VS lactate, the right panel of Fig. 5C). Percentage of ¹³C-labeling lactate derived from [1,2,3-¹³C₃]glucose is calibrated using 1.4 ([U-¹³C]lactate VS lactate, the right panel of Fig. 5D). The data before calibration are from Tables 2 and 4.