Table 2.

Transfer rates by biochemical classes on a total of 272 metabolites analyzed.

Taxonomy	n	${\mathit{n}}_{\mathit{R}>0.3}$ (%)	${\mathit{n}}_{0.1<\mathit{R}\le 0.3}$(%)
Amino Acid	98	4 (4%)	10 (10%)
Lipid	78	1 (1%)	11 (14%)
Xenobiotics	48	6 (12%)	2 (4%)
Nucleotide	13	0 (0%)	1 (8%)
Peptide	13	0 (0%)	1 (8%)
Cofactors and Vitamins	8	0 (0%)	0 (0%)
Carbohydrate	6	0 (0%)	0 (0%)
Energy	5	0 (0%)	2 (40%)
Partially Characterized Molecules	3	0 (0%)	1 (33%)