Figure 2.

GFAP immunoblot of ¹⁵N-labeled GFAP proteins and patient total homogenate samples. For each ¹⁵N-labeled GFAP standard (lanes 1–3), 7.5 ng of purified standard was loaded on the gel. The amounts of total protein applied for the R239H, R416W, and R79C patient samples (lanes 5–7) were 200 ng, 4,600 ng, and 270 ng, respectively. These patient protein amounts reflected differences in GFAP content, which were determined by densitometric comparison of GFAP staining intensity in pilot gels with that of the ¹⁵N-labeled GFAP standards. The negative control (lane 4) had no protein loaded. The positions of relevant molecular mass markers run concurrently are indicated.