Enables acetylgalactosaminyltransferase activity; glycosaminoglycan binding activity; and manganese ion binding activity. Involved in N-acetylglucosamine metabolic process and UDP-N-acetylgalactosamine metabolic process. Predicted to be located in cytosol; endoplasmic reticulum; and nucleoplasm. Is expressed in several structures, including central nervous system; genitourinary system; liver; lung; and spleen. Orthologous to human EXTL2 (exostosin like glycosyltransferase 2). [provided by Alliance of Genome Resources, Apr 2022]