Frequently Asked Questions Live Chat and Frequently Asked Questions are available for this Product. 包装 1, 5 g in ampule 50, 100, 500 mg in ampule Sealed ampule Biochem/physiol Actions all-trans-Retinoic acid (ATRA) is a ligand for both the retinoic acid receptor (RAR) and the retinoid X receptor (RXR). The bound RAR and RXR act as transcription factors that regulate the growth and differentiation of both normal and malignant cells. Cytochromes P450 (CYPs) catalyze the 4-hydroxylation of ATRA. Retinoic acid primes embryonic stem cells to become neurons. Other Notes Tandem Mass Spectrometry data independently generated by Scripps Center for Metabolomics is available to view or download in PDF. R2625.pdf Tested metabolites are featured on Scripps Center for Metabolomics METLIN Metabolite Database. To learn more, visit sigma.com/metlin.