Purification and properties of the carbonic anhydrase ofRhodospirillum rubrum

✍ Scribed by Steven R. Gill; Paula J. Fedorka-Cray; Rodney K. Tweten; Bayard P. Sleeper

• Book ID: 104764013
• Publisher: Springer
• Year: 1984
• Tongue: English
• Weight: 714 KB
• Volume: 138
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00413010

✦ Synopsis

The carbonic anhydrase (EC 4.2.1.1) of Rhodospirillum rubrum has been purified to apparent homogeneity and some of its properties have been determined. The enzyme was cytoplasmic and was found only in photosynthetically grown cells. It had a molecular weight of about 28,000, and was apparently composed of two equal subunits. The amino acid composition was similar to that of other reported carbonic anhydrases except that the R. rubrum enzyme contained no arginine. The isoelectric point of the enzyme was 6.2 and the pH optimum was 7.5. It required Zn(II) for stability and enzymatic activity. The Km(CO2) was 80 raM. Typical carbonic anhydrase inhibition patterns were found with the R. rubrum enzyme. Strong acetazolamide and sulfanilamide inhibition confirmed the importance of Zn(II) for enzymatic activity as did the anionic inhibitors iodide, and azide. Other inhibitors indicated that histidine, sulfhydryl, lysine and serine residues were important for enzymatic activity.