JOURNAL OF BASIC AND CLINICAL HEALTH SCIENCES, cilt.6, sa.3, ss.851-857, 2022 (ESCI)
Purpose: Increasing evidence in recent years highlights the predictive and prognostic importance of the expression of DNA repair proteins in cancer treatment. Generally, western-blotting or immunohistochemical staining methods are often used to determine the expression of DNA repair proteins. These methods might cause misleading results such as binding to nonspecific molecules by cross-reaction or false negativity as a result of the inability of antibodies to bind; absolute quantitation of proteins can not be performed. In this study, an analytical measurement technique was developed for human apurinic/apyrimidinic endonuclease 1 (hAPE1) protein for identification and absolute quantification in human leukocyte sample using high resolution mass spectrometry (HR-MS) with the targeted proteomics-based approach.Methods: Sample preparation was performed by using density gradient centrifugation and total protein extraction cartridges. hAPE1 was analyzed by liquid chromatography isotope-dilution-HR-MS (LC-HR-MS). A fully 15N-labeledResults: Six peptides were identified, which matched to a subset of the theoretically predicted tryptic peptides of hAPE1. Mass accuracy was calculated as <1.8 ppm. The amount of hAPE1 protein was calculated as 0.07 ngConclusion: The absolute quantification of APE1 protein performed within the scope of this study is expected to be used for the follow-up of the prognosis, response to treatment and survival rates of various cancer patients.