title: Characterisation of an acid trehalase produced by the thermotolerant fungus Rhizopus microsporus var. rhizopodiformis: biochemical properties and immunochemical localisation.
abstract: An acid trehalase from Rhizopus microsporus var. rhizopodiformis was purified to apparent homogeneity. The molecular weight by SDS-PAGE (60 kDa) or Sephacryl S-200 filtration (105 kDa) suggested a homodimer. The carbohydrate content was 72%. Endoglycosidase H digestion resulted in one sharp band of 51.5 kDa in SDS-PAGE. pH and temperature optima were 4.5 and 45 degrees C, respectively. The isoelectric point was 6.69 and activation energy was 1.14 kcal mol(-1). The enzyme was stable for 1 h at 50 degrees C and decayed at 60 degrees C (t50 of 1.3 min.). Apparent KM for trealose was 0.2mM. Immunolocalisation studies showed the enzyme tightly packed at the surface of the cells.
authors.affiliation: Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14.040-901 Ribeirão Preto, SP, Brazil.
authors.forename: Ana Carla Medeiros Morato
authors.initials: AC
authors.lastname: de Aquino
authors.forename: Simone Carvalho
authors.initials: SC
authors.lastname: Peixoto-Nogueira
authors.forename: João Atílio
authors.initials: JA
authors.lastname: Jorge
authors.forename: Héctor Francisco
authors.initials: HF
authors.lastname: Terenzi
authors.forename: Maria de Lourdes Teixeira de Moraes
authors.initials: Mde L
authors.lastname: Polizeli
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D019281:Dimerization; D004492:Edetic Acid / Q000494:pharmacology; D020536:Enzyme Activators / Q000494:pharmacology; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007700:Kinetics; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase / Q000378:metabolism; D008670:Metals / Q000494:pharmacology; D008970:Molecular Weight; D012233:Rhizopus / Q000737:chemistry* / Q000201:enzymology*; D013696:Temperature; D014198:Trehalase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D014199:Trehalose / Q000378:metabolism
chemical_list: D002241:Carbohydrates; D020536:Enzyme Activators; D008670:Metals; D004492:Edetic Acid; D014199:Trehalose; D014198:Trehalase; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase