<span style="mso-bidi-language:HI">An improved method for Isolation of photosystem <span style="mso-bidi-font-family:Arial;mso-bidi-language:HI">II <span style="mso-bidi-language:HI">from marine alga <i>Porphyra yezoensis </i>Udea </span></span></span>

Abstract

<span style="mso-bidi-language:HI">An improved method for isolation and characterization of photosystem (PS)II particles from thylakoid membranes of gametophytes of a marine alga <i>Porphyra yezoensis </i>Udea is reported. Thylakoid membranes were isolated using ultracentrifugation and differential speeds centrifugation and were further purified by the first sucrose density gradient centrifugation (SOGC). PSII particles with high 2, 6-

<span style="mso-bidi-language:HI">dichloroindophenol (OCIP) photo-reduction activity were isolated by the second SOGC from the thylakoid membranes. Absorption and fluorescence spectra of the thylakoid membranes and PSII particles were recorded and their polypeptides composition was studied. Thylakoid membranes obtained by the above two methods showed similar spectral properties and polypeptides composition. PSII particles, in addition to common extrinsic proteins found in PSII of other plants, contained cyt <i><span style="mso-bidi-font-family:Arial;mso-bidi-language:HI">c-</span></i><span style="mso-bidi-font-family:Arial;mso-bidi-language:HI">550<i>, </i><span style="mso-bidi-language:HI">a 20 kDa protein, along with two newproteins (14 kDa and 16 kDa).

</span></span></span></span>