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Cultures of Chlamydomonas r. do not express the gene for alkaline phosphatase when inorganic phosphate is in the medium; however, the enzyme is present when β-glycerophosphate is added. The carbon source plays an important role in the synthesis of the phosphatase; in fact, the acetate functions as a co-inducer of a series of structural genes.

The FDP-aldolase I from Euglena gracilis is a four-chain enzyme, as shown by the amino acid analysis of the C and N terminals. The protein is dissociated by acid pH to a monomer. The reassociation-dissociation process goes through a dimer stage. The enzyme, inhibited either by mercurials or by ATP, is dissociated to a dimer. This process is readly reversible either by mercaptoethanol and by AMP.

Fructose diphosphate aldolase has been purified from Candida utilis. The final product is homogeneous by several criteria and stable for several weeks in the presence of a reducing agent. The molecular weight from equilibrium sedimentation measurement is 67,500. The enzyme contains 1 mole of zinc per mole of enzyme and is activated by K+ ions; in these properties it resembles the enzyme from Saccharomyces cerevisiae. It is strongly inhibited by chelating agents such as EDTA, o-phenanthroline, and pyrophosphate. The enzyme catalyzes the cleavage of sedoheptulose 1,7-diphosphate and fructose 1-phosphate; the reaction rates with these substrates are 2.5 and 0.08% of that with fructose 1,6-diphosphate, respectively. No evidence was obtained for the formation of a Schiff base intermediate with the Candida enzyme. Since transaldolase from C. utilis does form a Schiff base intermediate, this organism represents a case in which both types of enzyme are present.

The unicellular green alga Chlamydomonas reinhardii contains two distinct aldolases (fructose-1, 6-diphosphate D -glyceraldehyde-3-phosphate-lyase, EC 4.1.2.13). These two enzymes are synthesized under different growth conditions: the alga can contain aldolase I or aldolase II or both of them. The two proteins are localized in the cytoplasm and they have been purified and compared, using kinetic and physical parameters. One resembles the prototype rabbit muscle aldolase, the other is a metalrequiring enzyme.