ISSN:
1432-072X
Keywords:
Rhodophyta
;
Cyanidium caldarium
;
Biliprotein
;
Levulinic acid
;
δ-aminolevulinic acid incorporation
;
Phycocyanin apoprotein
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Cultures of the unicellular red alga Cyanidium caldarium were transferred from heterotrophic growth conditions to photoautotrophic growth. During photoautotrophic growth, the biliprotein phycocyanin is synthesized de novo. In the presence of 2–5 mM/l levulinic acid which inhibits the biosynthesis of tetrapyrrole chromophores, phycocyanin biosynthesis is suppressed by a factor of 29. Immunoprecipitation yields small amounts of “apoprotein” i.e. phycocyanin which lacks all or part of its chromophore(s). In various experiments the ratio apoprotein/residual holoprotein (phycocyanin) was determined as 2–6 to one. Incubation with [3H]leucine leads to labelled immunoprecitable material: apoprotein (18,300–19,600 Mr) and larger poly-peptides (50,000–52,000 Mr) of unknown nature. The apoprotein was separated from residual phycocyanin by chromatography on DEAE-cellulose and preparative isoelectric focusing (IEF). The significance of the results for further studies on the last steps of phycocyanin biosynthesis is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00419478
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