May have weak glycosidase activity towards glucuronylated steroids. However, it lacks essential active site Glu residues at positions 241 and 874, suggesting it may be inactive as a glycosidase in vivo. May be involved in the regulation of calcium and phosphorus homeostasis by inhibiting the synthesis of active vitamin D (By similarity). Essential factor for the specific interaction between FGF23 and FGFR1 (By similarity). The Klotho peptide generated by cleavage of the membrane-bound isoform may be an anti-aging circulating hormone which would extend life span by inhibiting insulin/IGF1 signaling. a beta-D-glucuronoside + H2O = an alcohol + D-glucuronate Homodimer. Interacts with FGF23 and FGFR1. Isoform 1 shedding leads to a soluble peptide. Contains 2 glycosyl hydrolase 1 regions. However, the first region lacks the essential Glu active site residue at position 241, and the second one lacks the essential Glu active site residue at position 874. Belongs to the glycosyl hydrolase 1 family. Klotho subfamily. The thread of life - Issue 65 of December 2005