Enzymatic systems of inorganic pyrophosphate bioenergetics in photosynthetic and heterotrophic protists: remnants or metabolic cornerstones? Autores/as José R. Pérez-Castiñeira Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas “Isla de la Cartuja”, Universidad de Sevilla-CSIC, Seville, Spain Rosario Gómez-García Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas “Isla de la Cartuja”, Universidad de Sevilla-CSIC, Seville, Spain Rosa L. López-Marqués Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas “Isla de la Cartuja”, Universidad de Sevilla-CSIC, Seville, Spain Manuel Losada Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas “Isla de la Cartuja”, Universidad de Sevilla-CSIC, Seville, Spain Aurelio Serrano Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas “Isla de la Cartuja”, Universidad de Sevilla-CSIC, Seville, Spain Palabras clave: inorganic pyrophosphate, soluble inorganic pyrophophatase, proton-translocating pyrophosphatase, photosynthetic protists, parasitic protists Resumen An increasing body of biochemical and genetic evidence suggests that inorganic pyrophosphate (PPi) plays an important role in protist bioenergetics. In these organisms, two types of inorganic pyrophosphatases [EC 3.6.1.1, namely soluble PPases sPPases) and proton-translocating PPases H+-PPases)] that hydrolyse the PPi generated by cell anabolism, thereby replenishing the orthophosphate pool needed for phosphorylation reactions, are present in different cellular compartments. Photosynthetic and heterotrophic protists possess sPPases located in cellular organelles plastids and mitochondria), where many anabolic and biosynthetic reactions take place, in addition to H+-PPases, which are integral membrane proteins of the vacuolysosomal membranes and use the chemical energy of PPi to generate an electrochemical proton gradient useful in cell bioenergetics. This last category of proton pumps was considered to be restricted to higher plants and some primitive photosynthetic bacteria, but it has been found recently in many protists microalgae and protozoa) and bacteria, thus indicating that H+-PPases are much more widespread than previously thought. No cytosolic sPPase in bacteria, fungi and animal cells) has been shown to occur in these lower eukaryotes. The widespread occurrence of these key enzymes of PPi metabolism among evolutionarily divergent protists strongly supports the ancestral character of the bioenergetics based on this simple energy-rich compound, which may play an important role in survival under different biotic and abiotic stress conditions. Descargas PDF (English) Publicado 2010-03-12 Número Vol. 4 Núm. 3 (2001) Sección Review Articles Licencia Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. The corresponding author signs for and accepts responsability for releasing this material and will act on behalf of any and all coauthors regarding the editorial review and publication process.If an article is accepted for publication in International Microbiology, the authors (or other copyright holder) must transfer to the journal the right–not exclusive–to reproduce and distribute the article including reprints, translations, photographic reproductions, microform, electronic form (offline, online) or any other reproductions of similar nature. Nevertheless, all article in International Microbiology will be available on the Internet to any reader at no cost. The journal allows users to freely download, copy, print, distribute, search, and link to the full text of any article, provided the authorship and source of the published article is cited. The copyright owner's consent does not include copying for new works, or resale. In these cases, the specific written permission of International Microbiology must first be obtained.Authors are requested to create a link to the published article on the journal's website. The link must be accompanied by the following text: "The original publication is available on LINK at <http://www.im.microbios.org>. Please use the appropiate URL for the article in LINK. Articles disseminated via LINK are indexed, abstracted, and referenced by many abstracting and information services, bibliographic networks, subscription agencies, library networks, and consortia.