title: Electron microscopic and biochemical evidence that proline-beta-naphthylamidase is composed of three identical subunits.
abstract: Electron microscopy of pig intestinal proline-beta-naphthylamidase revealed that the enzyme is composed of 3 subunits, which are assembled in a trifoliolate shape. At pH 4.5 and 4 degrees C, the enzyme dissociates reversibly into active subunits in 4 h. Dissociation also occurs at higher pHs when the enzyme concentration is very low. The activity per mg protein of the native, trimeric enzyme is about 2.5-fold higher than that of the dissociated enzyme.
authors.affiliation: Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Nishigai
authors.forename: A
authors.initials: A
authors.lastname: Ikai
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
mesh_terms: D000626:Aminopeptidases / Q000378:metabolism / Q000648:ultrastructure*; D000818:Animals; D002850:Chromatography, Gel; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000201:enzymology*; D011487:Protein Conformation; D011489:Protein Denaturation; D013552:Swine
chemical_list: D000626:Aminopeptidases