|Selected aspects of the mannitolmetabolism, which is quite unusual for red algae, have been investigated. In this process the first anabolic enzyme of the pathway was isolated from the macroalga Caloglossa leprieurii and nearly completely purified after the successful development of a purification protocol. Examinations via electrophoresis confirmed the purity of the protein and determined the molecular weight slightly > 50 kDa. The protein identity was confirmed via photometric measurements of the specific enzyme activity as well as in vivo staining after a native electrophoresis.
All four enzymes of the mannitol cycle could be verified in the microalgae Rhodella violacea and Dixoniella grisea for the first time via the photometric measurement of the specific enzyme activities, but only Rhodella was investigated in more detail. In this process the enzyme kinetic characteristics of all four enzymes have been determined. An ecophysiological characterization of Rhodella via measurement of the growth rates according to different salinities and light conditions was performed for the first time.