The role of the circulation in processing pro-brain natriuretic peptide (proBNP) to amino-terminal BNP and BNP-32.
Human proBNP (purified from cardiac tissue) was incubated at 37 degrees C in whole blood, serum and plasma and the products analyzed by size exclusion high pressure liquid chromatography and radioimmunoassay (RIA). In addition to RIAs for BNP-32 and NT-proBNP(1-13), a newly developed RIA for proBNP(62-76) was also used to identify the peptides. Incubation with serum resulted in the formation of a 9 kDa and a 3 kDa peptide, consistent with the N-terminal and the C-terminal peptides of the propeptide. Minimal processing of proBNP was seen in blood or plasma, suggesting that the circulation does not play a major role in the activation of proBNP. Analysis of degradation products of human proBNP using site directed specific antisera indicates that removal of N-terminal amino acids from proBNP occurs in serum. These findings support the view that the "high molecular weight BNP-32" previously identified in human plasma comprises amino-terminal deleted forms, and is unlikely to be intact proBNP(1-108).
Hunt
P J
PJ
Department of Endocrinology, Christchurch Hospital, New Zealand.
Espiner
E A
EA
Nicholls
M G
MG
Richards
A M
AM
Yandle
T G
TG
D000328:Adult; D001798:Blood Proteins / Q000378:metabolism; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006325:Heart Atria / Q000737:chemistry; D006801:Humans; D008297:Male; D020097:Natriuretic Peptide, Brain; D009419:Nerve Tissue Proteins / Q000097:blood* / Q000302:isolation & purification / Q000378:metabolism*; D010446:Peptide Fragments / Q000097:blood* / Q000302:isolation & purification / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011863:Radioimmunoassay
D001798:Blood Proteins; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; C076910:brain natriuretic peptide, porcine