By using laser light scattering (LS) and size exclusion chromatography combined LS, we have investigated the molecular weight and chain conformation of amylopectin from rice of India (II-b), japonica (IJ-b), and glutinous (IG-b) in dimethyl sulfoxide (DMSO) solution. The weight-average molecular weight (M,,) and radius of gyration (< S-2 >(1/2)) of amylopectin were determined to be 4.06 x 107 and 128.5 nm for India rice, 7.41 x 10(7) and 169.6 nm for japonica rice, 2.72 x 10(8) and 252.3 nm for glutinous rice, respectively. The < S-2 >(1/2) values were much lower than that of normal polymers, indicating a small molecular volume of amylopectin, as a result of highly branched structure. Ignoring the difference of degree of branching, approximated dependences of (< S-2 >(1/2) and intrinsic viscosity ([eta]) on M-w for amylopectin in DMSO at 25 degrees C were estimated to be < S-2 >(1/2) = 0.03M(w)(0-35) (nm) and [eta] = 0.0331M(w)(0.41) (mL g(-1)) in the M-w range studied. Moreover, from the < S-2 >(1/2) values of numberless fractions obtained from many experimental points in the SEC chromatogram detected with LS, the dependence of < S-2 >(1/2) on M-w for the II-b sample was estimated also to be < S-2 >(1/2) = 0.34 Mw(0.347), coinciding with the above results. (c) 2007 Wiley Periodicals, Inc.