title: Substrate specificity of manganese-activated prolidase in control and prolidase-deficient cultured skin fibroblasts.
abstract: Skin fibroblasts have a single enzyme, Mn2+-activated prolidase, that hydrolyses a range of amino acid-proline dipeptides. Two cases of prolidase deficiency showed a marked loss of activity against glycyl-proline irrespective of Mn2+ conditions. However, the abnormal enzyme showed only moderate reductions in activity against phenylalanyl-, alanyl-, and leucyl-proline following preincubation with Mn2+ or addition of Mn2+ with the substrate. Control prolidase was stable to prolonged preincubation with Mn2+, whereas the abnormal prolidase was progressively inactivated. The findings indicate, for at least the present two cases, that prolidase deficiency results from an altered rather than a marked reduction in the amount of normal enzyme.
mesh_terms: D000592:Amino Acid Metabolism, Inborn Errors / Q000201:enzymology*; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004150:Dipeptidases / Q000172:deficiency*; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D008297:Male; D008345:Manganese / Q000378:metabolism*; D011392:Proline / Q000378:metabolism; D012867:Skin / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D008345:Manganese; D011392:Proline; D004150:Dipeptidases; C022449:proline dipeptidase