TABLE 3

Expression levels of phase II xenobiotic metabolizing enzymes in human skin and LabSkin

Protein identification and quantification was based on the presence of at least two different peptides and from human skin of at least two donors. Protein expression is represented by the mean, the S.D. of the mean (SD), and the percent CV. The range of protein expression (min–max) and the number of samples (n) are also reported. Protein abundance is reported in picomole milligram−1 of protein.

ProteinHuman SkinLabSkin 1LabSkin 2
Mean ± S.D. (CV)Range (n)Median
Glutathione transferases
 GSTK1 (kappa)9.99 ± 3.26 (32.67)6.47–15.24 (6)9.0518.996.73
 GSTM2 (mu)9.59 ± 4.07 (42.47)2.47–14.72 (6)10.0014.11
 GSTM3 (mu)a19.68 ± 10.29 (52.29)4.91–31.93 (6)22.908.8322.90
 GSTM4 (mu)21.75 ± 0.63 (2.91)21.28–22.47 (3)21.51
 GSTM5 (mu)a12.24 ± 5.33 (43.54)6.59–19.44 (4)11.475.94
 GSTO1 (omega)9.59 ± 3.43 (35.72)4.75–13.71 (6)9.048.947.83
 GSTP1 (pi)62.65 ± 17.78 (28.38)39.31–82.46 (6)60.2282.1030.45
 GSTT1 (theta)18.84 ± 3.31 (17.56)16.50–21.17 (3)18.847.31
 MGST111.26 ± 9.94 (88.27)2.69–22.16 (3)8.93
Sulfotransferases
 SULT1A4a4.08 ± 0.40 (9.73)3.84–4.54 (3)3.87
 SULT2B13.98 ± 2.21 (55.61)2.42–5.55 (2)3.98
Other transferases
 COMT10.13 ± 2.84 (28.06)5.31–13.25 (6)10.5829.7411.12
 MAT1Ab5.36 ± 1.87 (34.97)2.19–7.71 (6)5.484.254.57
 MPST3.97 ± 2.44 (61.52)1.21–5.86 (3)4.844.45
 NNMT6.01 ± 3.03 (50.43)2.74–8.73 (3)6.5715.475.65
 TGM34.83 ± 0.95 (19.73)3.81–5.70 (3)4.993.35
 TPMT3.27 ± 0.22 (6.73)3.11–3.42 (2)3.27
 TST3.36 ± 1.81 (53.86)1.66–6.44 (5) 6.44 6.442.825.203.08
  • TPMT, thiopurine S-methyltransferase; MAT1A, S-adenosylmethionine synthase isoform type-1.

  • a According to Human Protein Atlas, these enzymes are reported to be present in the skin at the RNA level (low copy numbers) but not at the protein level.

  • b According to Human Protein Atlas, these enzymes are not reported to be present in the skin at the RNA or protein level.