Photo courtesy of Cushman & Wakefield

After a successful conversion of office space into apartments, Cambridge-based 3JM Realty sold a downtown Boston property for $20 million.

The price equates to nearly $1,000 per square foot and $1.25 million per unit. The buyer is SC Alpha Inc., a Brookline-based entity that lists Apisit Limlomwongse as president.

The 20,025-square-foot building at 37-43 Temple Place in the Ladder Blocks section includes ground-floor retail space leased to Victoria’s Jewelry and The Crossing Wine & Spirits. The property includes 16 apartments that were completed in 2008.

The firm led by Morris Naggar has been one of the Downtown Crossing area’s most active housing developers in the past decade, breaking up upstairs office space into rental units at properties on Temple Place, Winter Street and Hamilton Place.

Cushman & Wakefield represented the seller and procured the buyer.