hyaluronan synthase; spHAS; seHAS; Alternating UDP-alpha-N-acetyl-D-glucosamine:beta-D-glucuronosyl-(1->3)-[nascent hyaluronan] 4-N-acetyl-beta-D-glucosaminyltransferase and UDP-alpha-D-glucuronate:N-acetyl-beta-D-glucosaminyl-(1->4)-[nascent hyalur • • •