It was most likely made by Ken-Wel for sale in a Schultz Novelty store. The patent stampings match the Vance patent stampings and the font on the "Professional" stamping is often seen on Ken-Wel gloves. If you visit
www.baseballglovecollector.com and search for "Schultz" you'll see a couple examples - two were made by Ken-Wel and one was made by D&M.