Construction has begun on a $10 million Holiday Inn hotel at the Maryland Trade Center Park in Greenbelt at the intersection of the Capital Beltway and the Baltimore-Washington Parkway. The hotel's owners announced last week that they had signed a franchise agreement with Holiday Inns of America Inc. earlier in March.

Coakley & Williams Inc., Greenbelt-based developers and operators of hotels and commercial properties, and Sunstates Properties Inc. of Raleigh, N.C., are the owners of the Maryland Trade Center Park and the hotel. Coakley & Williams is the general contractor for the project and will also manage and operate the hotel.

Coakley & Williams also owns and operates the Ramada Inn in Lanham, the Springfield Hilton in Springfield and the Henley Park Hotel in Washington, as well as about two million square feet of commercial and office space in the Washington area.

Other recent developments in commercial realty in the Washington metropolitan area:

* Business Computer Center has more than tripled its existing space during a remodeling and expansion project at 8659 Baltimore National Pike in Ellicott City. Business Computer's square footage rose from 500 to 1700 square feet of space.

* Hazleton Laboratories Corp.'s Kirschner Medical Division has purchased a 75,000-square-foot building in Timonium for relocation of its former West Coast operations in California and Washingtion state. The company manufactures prosthetic devices and surgical equipment and expects to initially employ 52 people. The capital investment for the project was about $3.5 million.

* Digital Equipment Corp. has leased 13,207 square feet of space at the International Square building at Connecticut Avenue and L Street NW. The Massachusetts-based Digital is relocating its Landover logistics group and opening a new sales office in Washington.

* Jefferson Standard Life Insurance Co. of Greensboro, N.C., has signed a lease for 4,928 square feet of space at Park Place in Rosslyn.

* R.M. Vredenburg and Co., a management engineering firm, has leased 14,715 square feet of space at 7926 Jones Branch Road in McLean.

* First American Bank N.A. has signed a 15-year lease for 5,862 square feet of space at 555 4th St. NW for a branch office.

* The Bread and Chocolate Restaurant has signed a 13-year lease for 1,716 square feet of space at 2301 M St. NW.

* A.Y. Cheung and Associates, an electronic engineering and design firm, has leased 3,000 square feet of space at 5026 Herzel Place in Beltsville.

American Video Entertainment Systems has leased 1,660 square feet of space at the Maryland Executive Park in Towson.