Katz was the forty-six-year old owner of Katz's Pharmacy and Soda Fountain. With his frail body, balding head, and yellow skin, he looked more like sixty-six. Katz hates the shop and despises his father for leaving it to him.
When Roland is looking for pencillin (as Jack Mort) he holds Katz up, and although Katz should have been nervous, he was glad there was a change in his routine. He gives Roland the pencillin and tells him "You will be the first person in history to hold someone up for pencillin."
Katz's jaw was broken during the course of the ensuing firefight.