This enzyme belongs to the family of lyases, specifically the carboxy-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is stipitatonate carboxy-lyase (decyclizing, stipitatate-forming). This enzyme is also called stipitatonate carboxy-lyase (decyclizing).
References
Bentley R, Thiessen CP (November 1963). "Biosynthesis of tropolones in Penicillium stipitatum. V. Preparation and properties of stipitatonic acid decarboxylase". The Journal of Biological Chemistry. 238: 3811–6. PMID14109225.