About PAPSS1
Three-prime-phosphoadenosine 5-prime-phosphosulfate (PAPS) is the sulfate donor cosubstrate for all sulfotransferase (SULT) enzymes (Xu et al., 2000 [PubMed 10679223]). SULTs catalyze the sulfate conjugation of many endogenous and exogenous compounds, including drugs and other xenobiotics. In humans, PAPS is synthesized from adenosine 5-prime triphosphate (ATP) and inorganic sulfate by 2 isoforms, PAPSS1 and PAPSS2 (MIM 603005).[supplied by OMIM, Mar 2008]

About Alexa Fluor 647
Alexa Fluor™ 647 (AF647, Alexa 647) has an excitation peak at 650 nm and an emission peak at 665 nm, and is spectrally similar to Cy®5 (GE Healthcare), iFluor® 647 (ATT Bioquest), and DyLight™ 650 (Thermo Fisher Scientific). Alexa 647 is commonly used for flow cytometry, microscopy, super-resolution microscopy applications. It is very bright, photostable, and pH insensitive, all of which contribute to sensitive detection while using this dye.