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Mara Z Vitolins,1 L Douglas Case,1 Stephen R Rapp,2 Mark O Lively,3 Edward G Shaw,4 Michelle J Naughton,5 Jeffrey Giguere,6 Glenn J Lesser7 1Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA; 2Department of Psychiatry and Behavioral Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA; 3Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC, USA; 4Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA; 5Department of Internal Medicine, The Ohio State University, Columbus, OH, USA; 6Greenville Community Oncology Research Program of the Carolinas, Greenville, SC, USA; 7Department of Internal Medicine-Hematology and Oncology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA Purpose: Women with breast cancer were randomized to receive coenzyme Q10 (CoQ10) plus Vitamin E or placebo in a clinical trial. The objective of this evaluation is to examine the association between participant self-reported adherence to the study supplements and changes in plasma biomarker levels.Patients and methods: Correlation coefficients quantified the association between changes in alpha-tocopherol and CoQ10 levels and the association between self-reported adherence and changes in biomarkers. Participants were categorized by self-reported adherence; Kruskal–Wallis tests compared changes in alpha-tocopherol and CoQ10 levels between self-reported adherence groups.Results: Women (N=155) provided baseline and post-treatment biomarkers; 147 completed at least one diary. While changes in alpha-tocopherol and CoQ10 levels were moderately correlated, correlations ranged from 0.40 to 0.48, association between self-reported adherence and plasma alpha-tocopherol or CoQ10 levels was weak; correlations ranged from 0.10 to 0.29 at weeks 8, 16, and 24. Some participants with high self-reported adherence actually had decreases in their biomarker levels.Conclusion: These findings support that self-reported adherence is likely to be overestimated. Biological and other measures of adherence that can better identify true adherence to study pills provided in clinical trials are greatly needed as they may assist in improving the interpretation of findings of future clinical trials. Keywords: adherence, self-report, blood biomarkers, clinical trial, CoQ10, alpha-tocopherol

Hen oviduct signal peptidase requires only two proteins for proteolysis of fully synthesized secretory precursor proteins in vitro: one with a molecular mass of 19 kilodaltons (kDa) and one which is a glycoprotein whose mass varies from 22 to 24 kDa depending on the extent of glycosylation. Purified signal peptidase has been analyzed both as part of an active catalytic unit and after electroelution of the individual proteins out of a preparative polyacrylamide gel. The multiple forms of the glycoprotein component of signal peptidase bind to concanavalin A and are shown to be derived from the same polypeptide backbone. Removal of their oligosaccharides by digestion with N-glycanase converts these proteins to a single 19.5-kDa polypeptide. The glycoproteins all exhibit very similar profiles following individual digestion with trypsin and separation of the resulting peptides by reverse-phase high-performance liquid chromatography. In addition, sequence analysis of selected peptides from corresponding regions in chromatograms representing each form of the glycoprotein reveals the same amino acid sequences. The 19-kDa signal peptidase protein does not bind concanavalin A, has a distinct tryptic peptide map from that of the glycoprotein, and appears to share no amino acid sequences in common with the glycoprotein. Its copurification on a concanavalin A-Sepharose column indicates that it must interact directly with the glycoprotein subunit.