7-Methylxanthine demethylase () is an enzyme with systematic name 7-methylxanthine:oxygen oxidoreductase (demethylating). This enzyme catalyses the following chemical reaction
The four substrates of this enzyme are 7-methylxanthine, reduced nicotinamide adenine dinucleotide (NADH), oxygen, and a proton. Its products are xanthine, oxidised NAD<sup>+</sup>, water, and formaldehyde.
The enzyme is a non-heme iron protein that is part of the pathway of caffeine degradation in Pseudomonas putida.