Brute is a commercial vehicle and heavy machine manufacturer in Grand Theft Auto IV. The vehicle division may be based off GMC, as GMC previously made medium to heavy-duty trucks and chassis. The Brute Ambulance looks similar to the Declasse Burrito, implying that Brute and Declasse are corporate cousins, much like Chevrolet (which Declasse is based) and GMC. Although no brand name is visible on the Mr. Tasty, it can be presumed that this vehicle is manufactured by Brute as it's basically a smaller Boxville.
In Grand Theft Auto V, Brute manufactures pumpjacks that are used in the Los Santos area.
A Brute pumpjack, as seen in the GTA V trailer.