Biotransformation is the chemical modification (or modifications) made by an organism on a chemical compound. If this modification ends in mineral compounds like CO2, NH4+, or H2O, the biotransformation is called mineralisation. Biotransformation means chemical alteration of chemicals such as nutrients, amino acids, toxins, and drugs in the body. It is also needed to render non-polar compounds polar so that they are not reabsorbed in renal tubules and are excreted. Biotransformation of xenobiotics can dominate toxicokinetics and the metabolites may reach higher concentrations in organisms than their parent compounds. [https://en.wikipedia.org/wiki/Biotransformation] Proteins on this pathway have targeted assays available via the [https://assays.cancer.gov/available_assays?wp_id=WP702 CPTAC Assay Portal] d32 Protein family phase I biotransformation pathway PW:0000857 Pathway Ontology cellular detoxification pathway PW:0000124 Pathway Ontology phase I biotransformation pathway via cytochrome P450 PW:0000375 Pathway Ontology 10781873 PubMed Molecular and structural aspects of xenobiotic carbonyl metabolizing enzymes. Role of reductases and dehydrogenases in xenobiotic phase I reactions. Toxicology 2000 Oppermann UC Maser E phase II biotransformation pathway PW:0000858 Pathway Ontology