A2LD1 is a 153 amino acid protein belonging to the gamma-glutamylcyclotransferase family. A2LD1 contains two exons, with only the second exon coding, and spans 2.2 kb. Consisting of a monomer subunit, A2LD1 participates in acyltransferase and gamma-glutamylcyclotransferase activities. A2LD1 assists with the breakdown of proteins cross-linked by transglutaminases. A2LD1 also catalyzes the formation of 5-oxoproline from L-gamma-glutamyl-L-epsilon-lysine, but is inactive with L-gamma-glutamyl-alpha-amino acid substrates, such as L-gamma-glutamyl-L-alpha-cysteine and L-gamma-glutamyl-L-alpha-alanine. A2LD1 is encoded by a gene that maps to human chromosome 13q32.3.