The Entner-Doudoroff Pathway for Glucose Degradation: the Work of MichaelDoudoroff
Year: 2005
Type: article
Abstract: Glucose and Gluconic Acid Oxidation of Pseudomonassaccharophila (Entner, N., and Doudoroff, M. (1952) J. Biol.Chem. 196,853–862) Michael Doudoroff (1911–1975) was born in St. Petersburg, Russia butmoved to San Francisco when he was 12 years old. He entered StanfordUniversity in 1929, planning to major in biology and specialize in entomology.However, as his exposure to different types of science broadened, he becamefascinated with bacteriology and protozoology. As a result, he studied thesurvival of Paramecium at elevated temperatures for his Master'sthesis with A. C. Giese and the adaptation of E. coli to elevatedsalt concentrations for his Ph.D. thesis with C. B. van Niel at the HopkinsMarine Station. While assisting van Niel in a course in general microbiology at the MarineStation, Doudoroff was introduced to the physiological and biochemicaldiversity of the microbial world. He subsequently started to study luminousbacteria, resulting in his discovery that riboflavin is directly involved inbacterial luminescence. Doudoroff also isolated a new species ofH2-oxidizing bacteria, Pseudomonas saccharophila, whichcould oxidize a number of mono-, di-, and polysaccharides. This was asurprising discovery because most bacteria only oxidize di- andpolysaccharides after first hydrolyzing them to monosaccharides. P.saccharophila, in fact, oxidized sucrose much more rapidly than itsconstituent monosaccharides, glucose and fructose. This anomaly was latershown to be caused by the lack of permeases in P. saccharophila formonosaccharides. In 1940, Doudoroff joined the bacteriology department at the University ofCalifornia, Berkeley. There he discovered that P. saccharophilaextracts catalyze the reversible formation of glucose 1-phosphate and fructosefrom sucrose and inorganic phosphate. He used the reverse reaction tosynthesize sucrose, a compound that had not yet been made by chemical orenzymatic methods. Doudoroff also used the synthetic reaction to make novelanalogues of sucrose by replacing fructose with d-ketoxylose andl-sorbose. He subsequently purified sucrose phosphorylase from P.saccharophila and studied its mode of action using radioactive inorganicphosphate. He learned that the enzyme is a transglucosidase that transfers theglucosyl residue from a suitable donor such as sucrose or glucose 1-phosphateto an appropriate acceptor such as fructose or orthophosphate. This was someof the first evidence for the formation of a substrate-enzyme complex as anintermediate in an enzymatic reaction. Doudoroff also discovered a second typeof phosphorolytic enzyme, maltose phosphorylase, in Neisseriameningitides. Doudoroff and his associates soon began to study the oxidative degradationof other sugars by P. saccharophila. He and Nathan Entner examinedthe enzymatic oxidation of glucose labeled with C14, as reported inthe Journal of Biological Chemistry (JBC) Classic reprinted here.They determined that glucose is phosphorylated to glucose 6-phosphate, whichis oxidized to 6-phosphogluconic acid. This compound is then split to giverise to pyruvic acid and glyceraldehyde phosphate.2-Keto-3-deoxy-6-phosphogluconate was thought to be an intermediate in thisreaction, and this was subsequently confirmed by Doudoroff and Joseph MacGeewho isolated and characterized the compound in 1954(1MacGee J. Doudoroff M. A newphosphorylated intermediate in glucose oxidation..J. Biol.Chem. 1954; 210: 617-626Abstract Full Text PDF PubMed Google Scholar). The enzyme that cleavedthe keto acid, ketodeoxyphosphogluconate aldolase, was later purified andcrystallized in 1967 (2Shuster C.W. Doudoroff M. Purificationof 2-keto-3-deoxy-6-phosphohexonate aldolases of Pseudomonassaccharophila..Arch. Mikrobiol. 1967; 59: 279-286Crossref PubMed Scopus (13) Google Scholar). These experiments eventually led to the formulation of the Entner-Doudoroffpathway, a series of reactions that catabolize glucose to pyruvic acid using adifferent set of enzymes from those used in either glycolysis or the pentosephosphate pathway. The novel feature of this pathway is the cleavage of6-phosphogluconate to yield pyruvate and glyceraldehyde 3-phosphate. Othersugars were shown to be metabolized by similar, but divergent, pathways. Later in his career, Doudoroff studied assimilatory processes in aerobicand photosynthetic bacteria and showed that poly-β-hydroxybutyric acid isan important energy reserve that is utilized by both intracellular andextracellular enzymes. He was also involved in an extensive clarification oftaxonomic and phylogenetic relationships in Pseudomonas and otheraerobic bacteria. The first publication resulting from this collaboration wasa massive survey of 169 phenotypic characters of 267 strains ofPseudomonas (3Stanier R.Y. Palleroni N.J. Doudoroff M. The aerobic pseudomonads: a taxonomic study..J.Gen. Microbiol. 1966; 43: 159-271Crossref PubMed Scopus (1805) Google Scholar). Doudoroff also had a profound influence on how bacteriology was taught atBerkeley. When he joined the faculty in 1940, the bacteriology coursesemphasized the medical and paramedical aspects of the subject. Doudoroffreorganized the curriculum to present bacteria and other microorganisms ascreatures whose structures, behaviors, and metabolic activities were worthy ofstudy independent of their roles in agriculture, industry, or disease. Heeventually, along with Roger Y. Stanier and Edward A. Adelberg, wrote thepopular textbook, The Microbial World, based on the Berkeleycourses. In recognition of Doudoroff's contributions to microbiology andbiochemistry he received the first Sugar Research Award from the NationalAcademy of Sciences in 1945 with Horace A. Barker and William Z. Hassid (bothof whom will be featured in future JBC Classics). He also became a J. S.Guggenheim Foundation fellow in 1949 and was elected to membership in theNational Academy of Sciences in1962. 1All biographical information on Michael Doudoroff was taken from Ref.4Barker H.A. Biographical Memoir ofMichael Doudoroff. 62. National Academy of Sciences, Washington D. C.1993: 118-141Google Scholar.1All biographical information on Michael Doudoroff was taken from Ref.4Barker H.A. Biographical Memoir ofMichael Doudoroff. 62. National Academy of Sciences, Washington D. C.1993: 118-141Google Scholar.
Source: Journal of Biological Chemistry
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1594199084