Hydrolyzes the polyglutamate sidechains of pteroylpolyglutamates. Progressively removes gamma-glutamyl residues from pteroylpoly-gamma-glutamate to yield pteroyl-alpha-glutamate (folic acid) and free glutamate. May play an important role in the bioavailability of dietary pteroylpolyglutamates and in the metabolism of pteroylpolyglutamates and antifolates. (6S)-5,6,7,8-tetrahydrofolyl-(gamma-L-Glu)(n) + (n-1) H2O = (6S)-5,6,7,8-tetrahydrofolate + (n-1) L-glutamate Homodimer. While its intracellular location is primarily the lysosome, most of the enzyme activity is secreted. Identified by mass spectrometry in melanosome fractions from stage I to stage IV. Isoform I (more expressed than isoform II in all tissues) is highly expressed in salivary gland, followed by kidney, liver, lung, stomach and uterus, and weakly expressed in small intestine, brain and fetal liver. Also expressed at a lower level in thymus, spleen and skeletal muscle. Also expressed in tumors. Belongs to the peptidase C26 family.