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This Article Full Text Full Text (PDF) All Versions of this Article: 293/6/H3550    most recent 00784.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Oliveira, E. B. Articles by Salgado, M. C. O. Search for Related Content PubMed PubMed Citation Articles by Oliveira, E. B. Articles by Salgado, M. C. O.

Carboxypeptidase B and other kininases of the rat coronary and mesenteric arterial bed perfusates

Departamentos de ¹Bioquímica e Imunologia e de ²Farmacologia da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil; and ³Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Brazil

Submitted 6 July 2007 ; accepted in final form 20 September 2007

We describe the enzymes that constitute the major bradykinin (BK)-processing pathways in the perfusates of mesenteric arterial bed (MAB) and coronary vessels isolated from Wistar normotensive rats (WNR) and spontaneously hypertensive rats. The contribution of particular proteases to BK degradation was revealed by the combined analysis of fragments generated during incubation of BK with representative perfusate samples and the effect of selective inhibitors on the respective reactions. Marked differences were seen among the perfusates studied; MAB secretes, per minute of perfusion, kininase activity capable of hydrolyzing 300 pmol of BK/min, which is 250-fold larger amount on a per unit time basis than that of its coronary counterpart. BK degradation in the coronary perfusate seems to be mediated by ANG I-converting enzyme, neutral endopeptidase 24.11-like enzyme, and a DL-2-mercaptomethyl-3-guanidinoethylthiopropanoic acid-sensitive basic carboxypeptidase; coronary perfusate of WNR contains an additional BK-degrading enzyme whose specificity resembles that of neurolysin or thimet oligopeptidase. Diversely, a des-Arg⁹-BK-forming enzyme, responsible for nearly all of the kininase activity of MAB perfusates of WNR and spontaneously hypertensive rats, could be purified by a procedure that involved affinity chromatography over potato carboxypeptidase inhibitor-Sepharose column and shown to be structurally identical to rat pancreatic carboxypeptidase B (CPB). Comparable levels of CPB mRNA expression were observed in pancreas, liver, mesentery, and kidney, but very low levels were detected in lung, heart, aorta, and carotid artery. In conclusion, distinct BK-processing pathways operate in the perfusates of rat MAB and coronary bed, with a substantial participation of a des-Arg⁹-BK-forming enzyme identical to pancreatic CPB.

bradykinin; angiotensin-converting enzyme; neutral endopeptidase; carboxypeptidase N; basic carboxypeptidase