Structure-dependent in vitro metabolism of alkyl-substituted analogues of. triphenyl phosphate in East Greenland polar bears and ringed seals

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1 1 SUPPORTING INFORMATION Structure-dependent in vitro metabolism of alkyl-substituted analogues of triphenyl phosphate in East Greenland polar bears and ringed seals 5 6 Adelle Strobel,, Robert J. Letcher,,*, William G. Willmore, Christian Sonne, Rune Dietz Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON, K1A 0H3, Canada Department of Biology, Carleton University, Ottawa, ON, K1S 5B6, Canada Department of Bioscience, Arctic Research Centre, Aarhus University, DK-4000 Roskilde, Denmark * Corresponding author: Robert J. Letcher; Phone: ; Fax: ; E- mail: robert.letcher@canada.ca. S1

2 Table S1: Pooled polar bear and ringed seal liver microsome protein content and enzymatic activity (ethoxyresorufin-o-deethylase (EROD)) at suspension dilution factors of 4 and 8 along with pooled microsomal SEM for technical replicates (n = 3). The positive control used was Wistar-Han rat microsomes. (Reproduced from Strobel et al ). Pooled Microsomes, Dilution Protein Content (mg/ml) (± SEM) (n = 3 rep.) Wistar-Han rat, 4x (± 1.633) (± 14.45) Ringed seal, 4x (± 6.163) (± 7.906) Ringed seal, 8x (± 1.109) (± 22.84) Polar bear, 4x (±1.479) 1006 (± 65.07) Polar bear, 8x (±0.7614) 1784 (± 82.11) EROD Activity pmol*min -1 *mg -1 ) (± SEM) (n = 3 rep.) S2

3 Table S2: Operating parameters of the tandem quadrupole MS/MS for the organophosphate ester (OPE) analysis of the fractions from the in vitro assays, which includes the multiple reaction monitoring (MRM) transitions. The OP triesters studied were isodecyl diphenyl phosphate (IDDPP), (p-tert-butylphenyl) diphenyl phosphate (TBPDPP), tris(p-tert-butylphenyl) phosphate (TTBPP), and two tris (isopropylphenyl) phosphate isomers (T2IPPP and T4IPPP) and where possible, the corresponding OP diester, diphenyl phosphate (DPHP). Mass-labeled internal standard parameters are also listed Compound MRM Transition Dwell (s) Cone (V) Collision (ev) Internal standard DPHP 507.3> d 10 -DPHP TBPDPP 383.1> d 21 -TCrP d 21 -TCrP 390.3> N/A IDDPP 391.2> d 21 -TCrP TIPPP 453.2> d 33 -T4IPPP d 33 -T4IPPP 486.4> N/A TTBPP 395.3> d 33 -T4IPPP DPHP in > ESI(+) 28 d 10 -DPHP d 10 -DPHP in ESI(+) 517.4> N/A DPHP in ESI(-) > d 10 -DPHP d 10 -DPHP in ESI(-) > N/A 38 S3

4 Table S3: After 100 min. of in vitro assay incubation, the percent conversion of nmol of parent organophosphate (OP) triester to the corresponding OP diester metabolite. The triesters presented are isodecyl diphenyl phosphate (IDDPP) and (p-tert-butylphenyl) diphenyl phosphate (TBPDPP), and their corresponding diester metabolite, diphenyl phosphate (DPHP). % Conversion is reproduced from the summary in Table 1. Polar bear OP triester or Administered OP Triester OP Diester diester conc. (mm) Depletion (nmol) a Formation (nmol) b % Conversion c IDDPP DPHP 63 4 TBPDPP DPHP Ringed seal OP triester or Administered OP Triester OP Diester diester conc. (mm) Depletion (nmol) a Formation (nmol) b % Conversion c IDDPP DPHP 60 7 TBPDPP DPHP a OP triester depletion is the administered concentration less the measured concentration at 100 minutes b OP diester formation is the concentration quantified at 100 minutes c Where % conversion = (OP diester formed) (OP triester depleted) x 100 % S4

5 TBPDPP r 2 = IDDPP r 2 = S5

6 T2IPPP r 2 = T4IPPP r 2 = S6

7 TTBPP r 2 = DPHP ESI(-) r 2 = S7

8 DPHP ESI(+) r 2 = Figure S1: Representative linear regressions for organophosphate (OP) triester and corresponding diester callibration curves by UPLC-ESI(+)-MS/MS analysis S8

9 Figure S2: Time course in vitro assay incubation of organophosphate (OP) triesters in ringed seal (RS) and polar bear (PB) liver microsomal assays for for IDDPP and TBDPP, which includes the diester metabolite formation, diphenyl phosphate (DPHP) over a 100 minute time course. OP triester depletion curves are reproduced from Figure 1. PBs are indicated by solid symbols, solid lines and RSs clear symbols, dotted lines. OP triester depletion is indicated by the darker colour and DPHP formation is shown with the lighter colour. Each data point is the mean of n = 3 replicate assays conducted on n = 2 different days (total of n = 6 replicates) and the error bars represent the ± SEM. Error bars are not shown where they are shorter than the height of the symbol. Asterisks indicate when the OP triester depletion or OP diester formation is significantly different (p < 0.01) compared to the concentration at one minute of incubation. 78 S9

10 References (1) Strobel, A.; Willmore, W. G.; Sonnne, C.; Dietz, R.; Letcher, R. J. Chemosphere 2018, 196, (2) Hanwell, M.; Curtis, D.; Lonie, D.; Vandermeersch, T.; Zurek, E.; Hutchison, G. Journal of Cheminformatics 2012, 4, S10