TABLE 1

Abundance of CYP enzymes and accessory proteins (P450 oxidoreductase, POR; cytochrome b5A, CYB5A) in a bank of liver microsomes measured by LC-MS/MS

Shown are the mean and CV% abundance values for the entire liver bank (N = 59) representing four different breeds and mixed-breed dogs, as well as for a subset of beagle dogs only (N = 25). Shown for comparison are abundance values reported by other investigators for the same CYPs in 18 beagle dogs by Heikkinen et al. (2015) using LC-MS/MS and in 12 beagle dogs by Eguchi et al. (1996) using ELISA.

ProteinMean (CV%) Liver Microsome Abundance (pmol/mg Protein)
This StudyHeikkinen et al. (2015)Eguchi et al. (1996)
All DogsResearch BeaglesResearch BeaglesResearch Beagles
(N = 59)(N = 25)(N = 18)(N = 12)
CYP1A13.1 (276)3.3 (247)
CYP1A289 (105)123 (104)37 (60)16 (57)a
CYP2A1311 (60)10 (66)
CYP2A258.1 (47)8.7 (39)
CYP2B1179 (52)86 (47)35 (34)51 (14)
CYP2C2154 (36)64 (32)70 (23)160 (21)
CYP2C41b8.2 (60)10 (48)
CYP2D15143 (27)139 (29)56 (39)
CYP2E173 (28)73 (26)36 (41)
CYP3A12124 (38)121 (28)93 (33)69 (29)
CYP3A263.7 (49)3.3 (46)2.7 (34)
POR40 (28)42 (27)
CYB5A431 (16)456 (17)
  • a Assumed to be primarily CYP1A2, but the ELISA method used did not distinguish between CYP1A1 and CYP1A2. “-” indicates that abundance of those proteins was not determined.

  • b Note that the results given for CYP2C41 are for dogs that express at least one copy of the CYP2C41 gene (12 dogs total, including four Beagles).