PAPSS2 (Hsap) PAPS synthase 2 bifunctional 3'-phosphoadenosine 5'-phosphosulfate synthethase 2 sulfate adenylyltransferase SK 2 3-prime-phosphoadenosine 5-prime-phosphosulfate synthase 2 PAPS synthetase 2 ATPSK2 ATP sulfurylase/adenosine 5'-phosphosulfate kinase adenylyl-sulfate kinase ATP sulfurylase/APS kinase 2 SK2 bifunctional 3'-phosphoadenosine 5'-phosphosulfate synthase 2 adenosine 5'-phosphosulfate kinase BCYM4 epididymis secretory sperm binding protein gene