Isolation and characterization of a 23 kDa protein essential for photosynthetic oxygen evolution

✍ Scribed by Christer Jansson; Hans -Erik Åkerlund; Bertil Andersson

• Publisher: Springer
• Year: 1983
• Tongue: English
• Weight: 556 KB
• Volume: 4
• Category: Article
• ISSN: 0166-8595
• DOI: 10.1007/bf00041823

✦ Synopsis

A 23 kDa protein has recently been demonstrated to participate in photosynthetic oxygen evolution by reconstitution experiments on inside-out thylakoid vesicles (Akerlund H-E, Jansson C and Andersson B (1982) Biochim Biophys Acta 681:1-10). Here we describe the isolation of the 23 kDa protein from a spinach chloroplast extract using ion-exchange chromatography. The protein was obtained in a yield of 25% and with less than 1% of contaminating proteins. The ability of the protein to stimulate oxygen evolution in inside-out thylakoids was preserved throughout the various fractionation steps. The isolated protein was highly water soluble and appeared as a monomer. Its isoelectric point was at pH --7.3. The amin O acid composition showed a high content of polar amino acids, resulting in a polarity index of 49%. The isolated protein lacked metals and other prosthetic groups. Its function as a catalytic or regulating subunit in the oxygen evolving complex is discussed.