Fig.1.

Calibration curve performance and definition. Detection of human recombinant (hr) full length (with 17 and 46 glutamines in the polyglutamine stretch) and N573 (with 23, 45, and 73 glutamines in the polyglutamine stretch) HTT protein by the 2B7-MW1 SMC assay. A) Polyglutamine and protein length-dependency in HTT detection were demonstrated analyzing the five proteins. B) A longer series of protein dilutions was analyzed for both the full length Q46 and the N573 Q45 in order to define the LLoQ and ULoQ of the assay. These two values were calculated as the lowest (above the LoD) and the highest points of the standard curve for which % CV and % RE are <25 [19]. They are 6.5 and 10000 fM for the large fragment and 16.5 and 10000 fM for the full length protein. The X and Y axes have logarithmic scales and the curves were fitted with a parameter logistic (5PL) model. Each point is the mean of 3 replicates. Bars represent standard deviation. LoD was calculated as the mean of the blank EP values plus three times the standard deviation.