You set up an in vitro translation system containing the ent

You set up an in vitro translation system containing the entire translation machinery but devoid of any component of the endoplasmic reticulum (ER) targeting machinery. To this system, you can add mRNA encoding either a 20 kDa secretory protein or a 20 kDa cytosolic protein. You perform in vitro translation in the presence of radioactively-labeled methionine, with or without the addition of saturating amounts of SRP or microsomes (think of these as mini-rough ER), as indicated below. After separating the protein products by SDS-PAGE and visualizing the radioactivity by autoradiography, you obtain the following results (see gel below). The presence or absence of each component in the reaction is indicated at the top of the corresponding lane(s) by and respectively. The numbers on the left indicate the apparent molecular mass (x1000) of bands on the gel. Which protein or Y) is the secretory protein? Which of the reactions (1 or 2) contained SRP?

Solution

Which protein (X or Y) is the secretory protein?

ANS: According to the given question the protein X is the secretory protein.

Which of the reactions (1 or 2) contained SRP?

ANS: The reactions 1 can contains the SRP.