Proteolysis in Euglena gracilis |
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Authors: | R Krauspe A Scheer S Schaper P Bohley |
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Affiliation: | (1) Institute of Plant Biochemistry, Academy of Sciences of the GDR, Weinberg 3, GDR-4020 Halle, German Democratic Republic;(2) Institute of Biochemistry, Medical Faculty, Martin-Luther-University, Hollystrasse 1, GDR-4020 Halle, German Democratic Republic |
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Abstract: | Endoproteolytic activities (EC 3.4.22. and 23.) of cell-free extracts of Euglena gracilis, measured by autolysis and azocaseinolysis, vary considerably during the culture growth cycle. They are high in the lag phase, drop sharply up to the mid-logarithmic phase, and then rise again reaching the initial high levels in the stationary phase. This pattern has been observed for both the soluble and the particulate proteolytic activities of four cell types differing with regard to the developmental state of the chloroplast: dark-grown, light-induced, and light-grown wild-type cells, as well as light-grown apoplastic W3BUL mutant cells, all on a glucose-based medium. Therefore, the activity of the main intracellular proteinases is neither directly nor indirectly light-regulated, but seems to be controlled by the availability of nutrients. Endogenous inhibitors of proteinases could not be detected. Cysteine proteinase activity has been found in the soluble and the particulate fractions, but aspartic proteinase activity in the latter ones only. Different cysteine proteinases may be present in the two fractions, during the different growth phases, and in the four cell types studied.Abbreviations CBB
Coomassie Brilliant Blue G-250
- DFP
diisopropyl fluorophosphate
- EDTA
disodium ethylendiaminetetraacetic acid
- E-64
l-transepoxysuccinyl-leucyl-amido(4-guanidino)butane
- Iog phase
logarithmic growth phase
- MET
2-mercaptoethanol
- PMSF
phenylmethylsulfonyl fluoride
- Z
benzyloxycarbonyl
Paper I of this series is Krauspe and Scheer (1986). A preliminary publication appeared (Krauspe et al. 1982) |
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Keywords: | Chloroplast Euglena (growth cycle proteinase) Inhibitor (proteinase) Proteinase (regulation) |
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