Isolation and Partial Characterization of an l -Amino Acid Oxidase and of Photosystem II Complexes from the Cyanobacterium Synechococcus PCC 7942

An L-amino acid oxidase with high specifity for basic L-amino acids was isolated from the cyanobacterium Synechococcus PCC 7942, and the enzyme was partially characterized. This enzyme was compared to the previously described L-amino acid oxidase from Synechococcus PCC6301 (G. Wälzlein, A. E. Gau, and E. K. Pistorius, Z. Naturforsch. 43c, 545-553, 1988). In addition, photosystem II complexes were isolated from Synechococcus PCC 7942, and it could be shown that a 36 kDa polypeptide which crossreacts with the antiserum raised against the L-amino acid oxidase (50 kDa) is present in isolated PS II complexes from Synechococcus PCC 7942 as already shown to be the case for Synechococcus PCC 6301 (A. E. Gau, G. Wälz­ lein, S. Gärtner, M. Kuhlmann, S. Specht, and E. K. Pistorius, Z. Naturforsch. 44c, 971-975 , 1989). These results clearly show that in isolated photosystem II complexes from Synechococ­ cus PCC 6301 as well as PCC 7942 a fourth polypeptide (besides D 1, D 2 and the manganese stabilizing protein) is present in the 30 kDa region and support our hypothesis suggesting that the water oxidizing enzyme is a separate protein (distinct from D 1 and D 2).