b1,3 glucan synthase is located in the plasma membrane (42). Electron microscopy of regenerating spheroplasts shows that the polysaccharide product is extracellular (29). Thus, the complex acts as a glycosyl transferase and transporter. Branches may be formed extracellularly by a putative branch-ing enzyme, Bgl2p, which has activity analogous to that of the starch branching enzymes