Synthesis and Application of New Rearranged Tetrapeptidyl Chloromethyl Ketones as Potent Proteinase K Inhibitor

The synthesis and proteolytic inhibitor function of two new tetrapeptides, MeOSuc-Ala-Pro-Ala-Val-CH2Cl (APAV) and MeOSuc-Ala-Pro-Ala-Leu-CH2Cl (APAL) are described. An examination of inhibitory activity using a realtime reverse transcription-polymerase chain reaction (RT-PCR) assay in the presence of proteinase K reveals that the APAL at a concentration of 0.5 mM allows a signal to be obtained for an exogenous target (“Xeno RNA”) at 29 cycles (i.e Ct = 29), whereas the MeOSuc-Ala-Ala-Pro-Val-CH2Cl (AAPV) control requires a 2-fold lower concentration (0.25 mM) to produce the same Ct. The other new analog APAV does not provide proteinase K inhibition under the same experimental conditions.