The type of inhibition of synthetic alpha-lactorphin (α-laf ) toward angiotensin I converting enyme was determined spectrophotometrically using the Holmquist method. Using Lineweaver-Burk plot the inhibitoin was found to be competitive. RP-HPLC analysis of reaction mixture showed the hydrolysis of α-laf in two dipeptides: YG and LF both inhibitors of the enzyme.

IC₅₀ of alpha-lactorphin toward inhibition of ACE and toward two opioids tests (Radio receptors assay on rat brain membrane and Guinea Pig ileum assay) were also evaluated in order to confirm previous published results.