Abstract
The stability of catalase, fumarase, and isocitrate lyase from deliberately broken organelles in crude extracts from endosperm tissue of castor bean seedlings has been examined. These enzymes are relatively stable at 2 C in extracts from endosperm of 2-day seedlings, but rapid losses of activity occur in extracts from older seedlings. These losses are shown to be brought about by the thiol-proteinase present in the extracts. The inclusion of 35% glycerol prevented the loss of catalase, fumarase, and isocitrate lysase activity, and various inhibitors of proteinases afforded limited protection. The most striking protectant was leupeptin, an inhibitor of serine and thiol-proteinases. Leupeptin completely inhibited the loss of activity of the three enzymes in crude extracts and improved yields when included in the grinding medium.
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Selected References
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- Gonzalez E., Beevers H. Role of the endoplasmic reticulum in glyoxysome formation in castor bean endosperm. Plant Physiol. 1976 Mar;57(3):406–409. doi: 10.1104/pp.57.3.406. [DOI] [PMC free article] [PubMed] [Google Scholar]
- RACKER E. Spectrophotometric measurements of the enzymatic formation of fumaric and cis-aconitic acids. Biochim Biophys Acta. 1950 Jan;4(1-3):211–214. doi: 10.1016/0006-3002(50)90026-6. [DOI] [PubMed] [Google Scholar]
- Tully R. E., Beevers H. Proteases and Peptidases of Castor Bean Endosperm: Enzyme Characterization and Changes during Germination. Plant Physiol. 1978 Nov;62(5):746–750. doi: 10.1104/pp.62.5.746. [DOI] [PMC free article] [PubMed] [Google Scholar]