ABSTRACT
INTRODUCTION Angiotensin-converting enzyme (ACE), as its name suggests, converts angiotensin I (Ang I) to angiotensin II (Ang II). This conversion is achieved by the removal of the two carboxy-terminal residues of Ang I; thus ACE is a dipeptidylcarboxypeptidase. Over the years, it has become apparent that ACE has other physiological substrates as well. The alternative substrates of ACE identified so far are all peptides, the most well studied one being the hormone, bradykinin . Action of ACE on both Ang I and bradykinin affects blood pressure regulation. However, there are strong experimental evidences to indicate that ACE can affect the functioning of the reproductive and the hematopoietic systems as well by acting upon additional substrates. In view of the research done over the last decade, the traditional view of ACE being a 'cardiovascular enzyme' should be expanded to include a broader physiological role of this enzyme. The modem view of ACE as the mediator of multiple regulatory processes is supported by the fact that it is expressed in many tissues and many cell types in the body.
