Mo. Rev. Stat. § 27.060: To represent state in other cases.

The attorney general shall institute, in the name and on the behalf of the state, all civil suits and other proceedings at law or in equity requisite or necessary to protect the rights and interests of the state, and enforce any and all rights, interests or claims against any and all persons, firms or corporations in whatever court or jurisdiction such action may be necessary; and he may also appear and interplead, answer or defend, in any proceeding or tribunal in which the state's interests are involved.