S.D. Codified Laws § 5-18A-34

The Bureau of Human Resources and Administration shall serve as the central procurement agency of the State of South Dakota. Except for the legislative and judicial branches and as otherwise specifically provided in this chapter and chapters 5-18B, 5-18C, and 5-18D, the Bureau of Human Resources and Administration shall procure, or authorize the procurement of all supplies and public improvements for state government. No claim for any such procurement may be paid unless authorization has been issued by the bureau. All state agencies and institutions are responsible for the procurement of services for their respective governmental unit. The governing body of all other purchasing agencies, including the legislative and judicial branches of state government, is responsible for procuring or authorizing the procurement of supplies, services, and public improvements for their respective governmental unit.