C. The experiment shown aims to determine whether ERp44 can bind also to a single C575, or rather to non-native bonds. Aliquots of the lysates from the indicated ERp44KO transfectants were precipitated with NP-Sepharose, resolved under non reducing conditions and the blot decorated with anti-λ antibodies or anti-ERp44 as indicated. Black asterisks point to covalent complexes of Halo-ERp44 with µs2L2. 