title: Spectroscopic and structural analysis of somatic and N-domain angiotensin I-converting enzyme isoforms from mesangial cells from Wistar and spontaneously hypertensive rats.
abstract: Angiotensin I-converting enzyme (ACE) plays a key role in the renin-angiotesin aldosterone cascade. We analysed the secondary structure and structural organization of a purified 65kDa N-domain ACE (nACE) from Wistar rat mesangial cells, a 90 kDa nACE from spontaneously hypertensive rats and a 130 kDa somatic ACE. The C-terminal alignment of the 65 kDa nACE with rat ACE revealed that the former was truncated at Ser(482), and the sequence of the 90 kDa nACE ended at Pro(629). Protein's secondary structure consisted predominantly of alpha-helices. The 90 and 65 kDa isoforms were the most stable in guanidine and at low pH, respectively. Enzymatic activity decreased with loss in secondary structure, except in the case of guanidine HCl where the 90 kDa fragment loses its secondary structure faster than its enzymatic activity. We identified and characterized the activity and stability of these isoforms and these findings would be helpful on the understanding of the role of nACE isoforms in hypertension.
authors.affiliation: Departamento de Medicina, Disciplina de Nefrologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Botucatu Street 740, Zip Code 04023-900, SP, São Paulo, Brazil.
authors.forename: Maria C C
authors.initials: MC
authors.lastname: de Andrade
authors.forename: Regina
authors.initials: R
authors.lastname: Affonso
authors.forename: Fernanda B
authors.initials: FB
authors.lastname: Fernandes
authors.forename: Andréia C
authors.initials: AC
authors.lastname: Febba
authors.forename: Ismael D C G
authors.initials: ID
authors.lastname: da Silva
authors.forename: Regina C R
authors.initials: RC
authors.lastname: Stella
authors.forename: Odair
authors.initials: O
authors.lastname: Marson
authors.forename: Guita N
authors.initials: GN
authors.lastname: Jubilut
authors.forename: Izaura Y
authors.initials: IY
authors.lastname: Hirata
authors.forename: Adriana K
authors.initials: AK
authors.lastname: Carmona
authors.forename: Hazel
authors.initials: H
authors.lastname: Corradi
authors.forename: K Ravi
authors.initials: KR
authors.lastname: Acharya
authors.forename: Edward D
authors.initials: ED
authors.lastname: Sturrock
authors.forename: Dulce E
authors.initials: DE
authors.lastname: Casarini
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004789:Enzyme Activation; D004795:Enzyme Stability / Q000187:drug effects; D019791:Guanidine / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006973:Hypertension / Q000201:enzymology; D007527:Isoenzymes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D050527:Mesangial Cells / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D007703:Peptidyl-Dipeptidase A / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D013057:Spectrum Analysis; D013696:Temperature
chemical_list: D007527:Isoenzymes; D007703:Peptidyl-Dipeptidase A; D019791:Guanidine