Biochemical and immunological properties of urinary
angiotensinase A and dipeptidylaminopeptidase IV.
Another consideration is that the mRNA transcribe from the gene ENPEP which encodes aminopeptidase A, also known as
angiotensinase A, a major metabolic enzyme of Ang II, is reduced and this could indicate a prolongation of the stimulation of [AT.sub.1] and [AT.sub.2] receptors by Ang II.
Scorpion venom contains a mixture of several low molecular weight basic proteins, neurotoxins, nucleotides, amino acids, oligopeptides, cardiotoxins, nephrotoxins, haemolytic toxins, phosphodiesterase, phospholipase A, hyaluronidase, acetylcholinesterase, glycosaminoglycans, histamine, serotonin, 5-hydroxyptamine and proteins that inhibit protease,
angiotensinase, succinate-dehydrogenase, ribonuclease, and 5-nucleotidase.
ACE inhibitor therapy did not significantly affect angiotensinase activity.
Not only that, but also, as the authors were focusing on membrane-bound angiotensinases, they may have not identified the potential effects of the soluble ACE2.
The amount of angiotensinase activity in plasma and its impact on PRA measurement has been shown in prior studies.
A range of angiotensinase activities has been described, and recently ACE 2, a new angiotensin-converting enzyme, was described that generates Ang I 1-9 by the removal of a single C-terminal amino acid (18).
AlaAP, which exhibits broad substrate specificity, may hydrolyze bradykinins (4) and enkephalins (16), and may also act as an
angiotensinase (17).
A method based on a wheat germ agglutinin extraction column combined with high-performance anion-exchange chromatography has been reported as a means to purify and analyze
angiotensinase A and aminopeptidase M in human urine and kidney samples (101).
PRA was measured by RIA of angiotensin I in the presence of reagents that inhibit angiotensin I-converting enzyme and
angiotensinases. The assay was performed according to the method of Sealy and Laragh (20, 21), using GammaCoat Plasma Renin Activity RIA Kits (DiaSorin).
The direct measurement of Ang2 is difficult because of its very low circulating concentrations (3, 4) and extremely short in vivo half-life as it is rapidly degraded to inactive polypeptide fragments by
angiotensinases in plasma and tissue (2).