Recent evidence from a mass spectrometry study found that pyruvate carboxylase, which catalyzes the conversion of pyruvate to oxaloacetate, was S-nitrosylated (and thus inhibited) in human postmortem brain samples from HIV-1-positive individuals with HAND and a history of METH use, but not in the HAND brains without METH abuse [46]. This evidence concerns the gene PC and HIV-associated neurocognitive disorder.