title: A new member of the leucyl aminopeptidase family purified and identified from a marine unicellular algae.
abstract: Leucyl aminopeptidase (LAP; EC 3.4.11.1) activity was purified from crude extracts of the marine unicellular algae Gonyaulax polyedra by a combination of hydrophobic interaction with phenyl sepharose, DEAE-cellulose, and mono-Q HR5/5 ion-exchange chromatography. The undenaturated protein has a molecular mass of about 110 kD and based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the enzyme appears to be composed of two possibly identical subunits of 55 kD. The identity of the protein was confirmed by a cross-reaction of the purified protein with an antibody raised against a commercial LAP. Biochemical characterization showed that the Gonyaulax enzyme was similar to most of the previously described LAPs. Gonyaulax LAP is a metallo-enzyme since EDTA and 1,10-phenathroline significantly inhibited activity. Addition of the metal ions Zn(2+), Cu(2+) inhibited 80% of LAP activity, suggesting they are not the natural cofactors of the enzyme. Other metals, such as Ca(2+), Co(2+), Mn(2+), or Mg(2+) (concentrations up to 4 mM), caused no alteration in the total activity of Gonyaulax LAP.
authors.affiliation: Instituto de Química, Universidade de São Paulo, C.P. 26077, São Paulo, SP, CEP, 05599-970, Brazil.
authors.forename: D
authors.initials: D
authors.lastname: Sankievicz
authors.forename: P
authors.initials: P
authors.lastname: Colepicolo
mesh_terms: D000818:Animals; D002845:Chromatography / Q000379:methods; D002940:Circadian Rhythm; D003429:Cross Reactions; D004141:Dinoflagellida / Q000201:enzymology*; D007931:Leucyl Aminopeptidase / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D008667:Metalloproteins / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D014452:Ubiquitins / Q000378:metabolism
chemical_list: D008667:Metalloproteins; D011506:Proteins; D014452:Ubiquitins; D007931:Leucyl Aminopeptidase