Active Mitochondria Do Not Produce Ethylene
1968; Oxford University Press; Volume: 43; Issue: 6 Linguagem: Inglês
10.1104/pp.43.6.999
ISSN1532-2548
Autores Tópico(s)Mitochondrial Function and Pathology
ResumoAlthough numerous reports on ethylene evolution from subcellular preparations have appeared (2,3, 4,5,8,9,11, 18, 19,20), some of these works have been criticized by Burg and Burg (1) and by Meigh (17). and the question whether or not mitochondria produce ethylene remains unclear. It is known that ethylene can be evolved nonenzymically from methionine and its derivatives, mediated either by ICu2+-ascorbate-H202 (10) or by FMN-light (22,23). Enzymic systems of ethylene production were described recently by Mapson and Wardale (13), Ku et al. (7), and Meheriuk and Spencer (14, 15, 16). More recently, Yang (21) has demonstrated that ethylene can rapidly be formed aerobically from methional by an enzyme system consisting of horseradish peroxidase, Mn2+ and sulfite ions, and a monohydric phenol. We have been able to isolate very active, homogeneous, relatively uninjured mitochondria from various fruits (6). It is the purpose of this article to indicate that such active mitochondria do not directly produce ethylene; it appears more likely that ethylene is produced by a soluble enzyme. Tomato fruits (Lycopersicon esculentum Mill., cv. VC 243-20) were harvested at various stages of maturity from greenhouse-grown plants (12). The fruits were washed with distilled water and chilled (0-4°) from 1 to 4 hours before processing by the method of Ku et al. (6). The flesh of the fruit wall was carefully removed, avoiding the inclusion of any skin, seeds, or the jelly-like tissue around the seeds.
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