A key factor in ordered lignin macromolecular assembly/configuration is in temporal and spatial control over monolignol radical generation (discussed below as regards template — facilitated polymerization). Since the 1950s, various oxidases have been implicated as having roles in lignification — these have included peroxidase (12, 53, 54, 171, 254—257), laccase (12, 53, 54, 258—266), combined peroxidase and laccase (12, 53, 54, 254, 267), coniferyl alcohol oxidase (268—271), (poly)phenol oxidase (272—278), and cytochrome oxidase (279). Their putative involvement has generally relied upon the ability of such enzymes to oxidize monolignols in vitro, even though none of these enzymes have yet engendered formation of products in vitro that duplicate faithful facsimiles of lignin structure; in some cases, they do not even generate formation of polymeric products. [The reader is again encouraged to review the historical developments as regards consideration of each of these oxidases and their potential for lignification and the mechanistic questions that they raise (31)].