Abstract:  Objective: To obtain homogeneous Porphyra yezoensis polysaccharides (PYPS) and determine corresponding Mark- Houwink constants. Method: PYPS were obtained as follows: ground and degreased by super critical fluid CO2, extracted in distilled water, and then precipitated by ethanol and purified by way of removing protein with chromatography on DEAE-52 column. Molecular weight and purity were identified by GPC. The Mark-Houwink equation constants were determined by 3 homogeneous PYPS, and validated. Results: Three purified PYPS are obtained with the molecular weight as 2.2×105, 3.8×105 and 6.1×105, respectively. The Mark-Houwink equation constants of PYPS in distilled water at 25℃ are: α=0.626 and K=7.86×10-3. Conclusion: The obtained K and α value are reliable, was confirmed by PYPS2 assays. The values could be applied in molecular weight studies on PYPS molecular weights.

Key words:  , Porphyra yezoensis polysaccharides； purification； Mark-Houwink equation；