were purchased
from Fisher Scientific (Pittsburgh, PA) or Sigma-Aldrich (St. Louis,
MO), unless otherwise stated. [13C2]Oxalic acid
(99% 13C) was purchased from Cambridge Isotope Laboratories
(Tewksbury, MA), and an oxalate assay kit was obtained from Trinity
Biotech USA (Jamestown, NY). Nickel-nitrilotriacetic acid agarose
(Ni-NTA) was supplied by Qiagen (Germantown, MD). DNA primers were
synthesized by Integrated DNA Technologies, Inc. (Coralville, IA),
and DNA sequencing was performed in the DNA Sequence Core at the University
of Michigan (Ann Arbor, MI). Protein concentrations were determined
using the CoomassiePlus Protein Assay reagent obtained from ThermoFisher
Scientific (Waltham, MA), and BT Chelex 100 resin was purchased from
Bio-Rad (Hercules, CA). ICP-MS measurements of metal content were
taken at the Center for Applied Isotope Studies at the University
of Georgia (Athens, GA).