The supernatants
were filtered through 0.45-lm nylon syringe filters, and then
1-ml samples were injected into the SEC-MALLS-RI system that
comprised a pump (P2000, Spectra System, San Hose, CA), injector
with a 1-ml loop, SEC column, MALLS (632.8 nm, DAWN DSP,
Wyatt Technology, Santa Barbara, CA), and an RI detector (Optilab
DSP, Wyatt Technology, Santa Barbara, CA) connected in series. The
flow rate of the eluent (50 mM LiBr in DMSO) was 0.6 ml/min