Massachusetts Mutual Life Insurance Co. bought Century Center, a three-story office building on La Alameda in Mission Viejo, in a transaction valued at $10.1 million from C.C. Business Partners in Irvine. . . . Auerbach Construction Inc. of Santa Monica is opening a county office at Stadium Towers Plaza in Anaheim to handle construction commitments of more than $20 million. . . . The Irvine Co. won awards Thursday from the National Assn. of Industrial and Office Parks for four sets of industrial buildings, including the Irvine/Koll Venture buildings on Technology Drive in Irvine.