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Tito Ureta

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In this Spanish name, the first or paternal surname is Ureta and the second or maternal family name is Aravena.
Tito Ureta
Born
Tito Ureta Aravena

(1935-10-10)10 October 1935
Iquique, Chile
DiedJune 9, 2012(2012-06-09) (aged 76)
Santiago, Chile
EducationUniversity of Chile
Scientific career
FieldsHexokinases, protein evolution
InstitutionsUniversity of Chile, Rockefeller University, New York
Thesis Formas moleculares multiples de ATP-D-hexosa 6-fosfotransferasa  (1982)
Academic advisorsHermann Niemeyer, Fritz Albert Lipmann

Tito Ureta Aravena (1935–2012) was a Chilean biochemist, known for studies of hexokinases in many organisms.

Personal life

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Tito Ureta was born on 10 October 1935 in Iquique, Chile, where he was educated at the Domingo Santa María School, and in the Liceo José Victorino Lastarria (Santiago).[1] He married Sara Elfriede Herbstaedt Yáñez.[2]

Education and early research

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Ureta's first university studies at the University of Chile were in medicine, and he qualified as a surgeon in 1963.[1] However, his interest turned to biochemistry and he devoted his career to research and experimental work, on hexokinases in particular.

In 1960 he joined the group of Hermann Niemeyer, with whom he obtained his doctorate on the basis of a thesis on the purification and characterization of the enzyme responible for phosphorylation of glucose in the mammalian liver.[3][4]

He completed his training in a post-doctoral period in the laboratory of Fritz Lipmann at the Rockefeller University in New York.[1][5]

Research career

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Ureta devoted much of his career to the study of hexokinases, mainly in mammals, but also in many other organisms, such as birds,[6] amphibians,[7] other vertebrates,[8] and fungi.[9][10]

Ureta and colleagues determined that there were four isoenzymes of hexokinase in rat liver, and proposed the sequence A, B, C, D on the basis of the order of elution from chromatographic columns of DEAE cellulose.[11] A little later Katzen and colleagues observed the same order for starch-gel electrophoresis and designated the isoenzymes as I, II, III and IV,[12] a terminology that has been widely adopted, for example by Agius and colleagues.[13]

Hexokinase A (or I), predominant in brain,[14] hexokinase B (or II), predominant in muscle,[15] and hexokinase D (or IV), predominant in liver hexokinase (or “glucokinase”),[16] have been extensively studied, but hexokinase C (or III) has received rather little attention, and Ureta is one of the few who have studied its properties.[7][17]

His study of the hexokinase isoenzymes in the rat led to a more general interest in the role of isoenzymes in metabolism.[18][19] His comparison of hexokinases from a wide variety of sources[20] stimulated a detailed study of the evolution of their structures.[21]

His interest was later devoted to the study of metabolic regulation in vivo, especially in relation to glycolysis,[22] the pentose phosphate pathway[23] and glycogen synthesis.[24] For these studies he used frog oocytes as a convenient tool, and he advocated their wide use.[25][26]

Books

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In his books (in Spanish) Ureta set out to bring his ideas on protein evolution[27] and on philosophy to a broad public.[28] In his preface to the latter book Humberto Maturana wrote as follows:

Éste es un libro enorme, no en su tamaño físico pero sí en su contenido. Abarca todas las dilensiones humanas, tanto de la persona como objeto de la atención del autor como en lo que revela acerca de este mismo.
(This is a huge book, not in its physical size, but in its content. It covers all human dimensions, both in terms of the person as the object of the author's attention and in what it reveals about the person.)

Society and editorial activities

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Ureta was President of the Society of Biology of Chile in 1977–1978, and of the Society of Biochemistry and Molecular Biology of Chile in 1983–1984, and participated in various other societies in Europe and in the USA.[1]

Between 1978 and 1992 he was Editor of Archivos de Biología y Medicina Experimentales,[1] the principal journal of experimental biology in Chile, now called Biological Research.[29]

In 2012 the Society of Biochemistry and Molecular Biology of Chile created the Tito Ureta Prize in his memory.[30] Notable recipients include Jorge Allende, Marta Bunster, María Luz Cárdenas and Pablo Valenzuela.

References

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  1. ^ a b c d e "Falleció destacadísimo bioquímico, Dr. Tito Ureta Aravena". Facultad de Ciencias Químicas y Faramcéuticas, Universidad de Chile.
  2. ^ Merino, R. A. (2023). "Sra. Elfriede Herbstaedt Yáñez (1930–2023)". Boletín de la Academia Chilena de Medicina. LX: 378–379.
  3. ^ "Formas moleculares multiples de ATP-D-hexosa 6-fosfotransferasa" (PDF). Sociedad de Bioquímica y Biología Molecular de Chile.
  4. ^ González, C.; Ureta, T.; Sánchez, R.; Niemeyer, H. (1964). "Multiple molecular forms of ATP: Hexose 6-phosphotransferase from rat liver". Biochem. Biophys. Res. Comm. 16 (4): 347–352. doi:10.1016/0006-291X(64)90038-5.
  5. ^ "Tito Ureta, M.D." Chemistry Tree. 2015.
  6. ^ Ureta, T.; Reichberg, S. B.; Radojkovic, J.; Slebe, J. C. (1973). "Comparative studies on glucose phosphorylating isoenzymes of vertebrates—IV. Chromatographic profiles of hexokinases from the liver of several avian species". Comparative Biochemistry and Physiology Part B: Comparative Biochemistry. 45 (2): 445–461. doi:10.1016/0305-0491(73)90076-X.
  7. ^ a b Ureta, T. (1976). "The allosteric regulation of hexokinase C from amphibian liver". J. Biol. Chem. 251 (16): 5035–5042. doi:10.1016/S0021-9258(17)33217-9.
  8. ^ Ureta, T.; Medina, C.; Preller, A. (1987). "The evolution of hexokinases". Arch Biol Med Exp. 20 (3–4): 343–357. PMID 8816075.
  9. ^ Lagos, R.; Ureta, T. (1980). "The hexokinases from wild-type and morphological mutant strains of Neurospora crassa". Eur. J. Biochem. 104 (2): 357–365.
  10. ^ Marcus, F.; Ureta, T. (1986). "Amino acid sequence homology between yeast hexokinases and rat hexokinase C". Biochem. Biophys. Res. Comm. 139 (2): 714–719. doi:10.1016/S0006-291X(86)80049-3.
  11. ^ González, C.; Ureta, T.; Sánchez, R.; Niemeyer, H. (1964). "Multiple molecular forms of ATP:hexose 6-phosphotransferase from rat liver". Biochem. Biophys. Res. Comm. 16 (4): 347–352. doi:10.1016/0006-291X(64)90038-5.
  12. ^ Katzen, H. M.; Soderman, D. D.; Nitowsky, H. M. (1965). "Kinetic and electrophoretic evidence for multiple forms of glucose-ATP phosphotransferase activity from human cell cultures and rat liver". Biochem. Biophys. Res. Comm. 19 (3): 377–382. doi:10.1016/0006-291X(65)90472-9.
  13. ^ Lowes, W.; Walker, M.; Alberti, K. G. M. M.; Agius, L. (1998). "Hexokinase isoenzymes in normal and cirrhotic human liver: suppression of glucokinase in cirrhosis". Biochim. Biophys. Acta. 1379 (1): 134–142. doi:10.1016/S0304-4165(97)00092-5.
  14. ^ Ureta, T.; Smith, A. D.; Wilson, J. E. (1986). "Hexokinase A from mammalian brain: Comparative peptide mapping and immunological studies with monoclonal antibodies". Arch. Biochem. Biophys. 246 (1): 419–427. doi:10.1016/0003-9861(86)90488-1.
  15. ^ Lueck, J. D.; Fromm, H.J. (1974). "Kinetics, mechanism, and regulation of rat skeletal muscle hexokinase". J. Biol. Chem. 249 (5): P1341-1347.
  16. ^ Niemeyer, H; Cárdenas, M L; Rabajille, E; Ureta, T; Clark-Turri, L; Peñaranda, J (1975). "Sigmoidal kinetics of glucokinase". Enzyme. 20 (6): 321–333. doi:10.1159/000458957. PMID 1193069.
  17. ^ Ureta, T.; Radojković, J.; Díaz, N.; Slebe, J. C.; Lozano, C. (1978). "Comparative studies on glucose phosphorylating isoenzymes of vertebrates: Identification and characterization of amphibian liver hexokinases". Arch. Biochem. Biophys. 186 (2): 235–247. doi:10.1016/0003-9861(78)90432-0.
  18. ^ Ureta, T. (1978). "The role of isozymes in metabolism: a model of metabolic pathways as the basis for the biological role of isozymes". Current Topics in Cellular Regulation. 13: 233–258. doi:10.1016/B978-0-12-152813-3.50011-2.
  19. ^ Ureta, T. (1982). "The comparative isozymology of vertebrate hexokinases". Comparative Biochemistry and Physiology Part B: Comparative Biochemistry. 71 (4): 549–555. doi:10.1016/0305-0491(82)90461-8.
  20. ^ Ureta, T.; Radojković, J.; Zepeda, S.; Guixé, V. (1981). "Comparative studies on glucose phosphorylating isoenzymes of vertebrates—VII. Mammalian hexokinases". Comparative Biochemistry and Physiology Part B: Comparative Biochemistry. 70 (2): 225–236. doi:10.1016/0305-0491(81)90038-9.
  21. ^ Cárdenas, M L; Cornish-Bowden, A; Ureta, T (1998). "Evolution and regulatory role of the hexokinases". Biochim. Biophys. Acta. 1401 (3): 242–264. doi:10.1016/S0167-4889(97)00150-X.
  22. ^ Guixé, V.; Preller, A.; Kessi, E.; Hofer, H. W.; Ureta, T. (1994). "Glycolysis is operative in amphibian oocytes". FEBS Lett. 343 (3): 219–222. doi:10.1016/0014-5793(94)80559-8.
  23. ^ Preller, A.; Guixé, V.; Ureta, T. (1999). "In vivo operation of the pentose phosphate pathway in frog oocytes is limited by NADP+ availability". FEBS Lett. 446 (1): 149–152. doi:10.1016/S0014-5793(99)00192-1.
  24. ^ Kessi, E.; Guixé, V.; Preller, A.; Ureta, T. (1996). "Glycogen synthesis in amphibian oocytes: evidence for an indirect pathway". Biochem. J. 315 (2): 455–460. doi:10.1042/bj3150455. PMC 1217217.
  25. ^ Ureta, T.; Radojković, J. (1985). "My favourite cell: Microinjected frog oocytes: a first-rate test tube for studies on metabolism and its control". BioEssays. 2 (5): 221–226. doi:10.1002/bies.950020510.
  26. ^ Ureta, T.; Preller, A.; Kessi, E. (2001). "Frog Oocytes: a living test tube for studies on metabolic regulation". IUBMB Life. 51 (1): 5–10. doi:10.1080/15216540117404.
  27. ^ Ureta, Tito (2010). Origen y evolución de proteínas y enzimas [Origin and evolution of proteins and enzymes]. Editorial Universitaria Santiago. ISBN 978-9561121003.
  28. ^ Ureta, Tito (2013). En el filo de la navaja de Occam [On the edge of Occam's razor]. Editorial Universitaria Santiago. ISBN 978-9561116870.
  29. ^ "Biological Research". BMC Part of Springer Nature. 2025.
  30. ^ "Reconocimientos: Premio Tito Ureta". Society of Biochemistry and Molecular Biology of Chile.
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