Renin-protein complex

Figure 7.11 Two different conformations of the enzyme renin when bound to two different inhibitors. The complex between renin (blue) and Compound 1 (red) is overlaid with renin (yellow) bound to Compound 2 (not shown in complex). Note the very different positions adopted by the sidechains of residues Trp39 and Tyr75. (Reprinted by permission from Teague, S.J. Implications of protein flexibility for drug discovery. Nat. Rev. Drug Discov. 2003, 2, 527-541. copyright 2003, Macmillan Publishers Ltd.)...

A study in spontaneously hypertensive rats found that aprotinin suppressed the hypotensive responses of captopril and enalapril. Aprotinin is a proteolytic enzyme inhibitor that has many actions including antagonism of the kallikrein-kinin system, which in turn affects bradykinins and renin. It would therefore be expected to have complex interaetions with the ACE inhibitors, whieh also affect these proteins. However, there does not appear to be any evidence to suggest that this theoretical interaction is of clinical relevance. 

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