Lipmann, Fritz Albert
LIPMANN, FRITZ ALBERT
(b. Königsberg, East Prussia [now Kaliningrad Oblast, Russia], 12 June 1899; d. Poughkeepsie, New York, 24 July 1986),
biochemistry, role of organic phosphates in metabolism, “energy-rich” bonds, coenzyme A, basic mechanisms of protein biosynthesis.
“There is no biochemist like Fritz Lipmann. He has always been at the heart of biochemistry … [and] occupies a pivotal position, his lab playing a central role in understanding how central metabolic processes … [work] … together.” (Organizer, 1969, p. vii)
Along with Otto Heinrich Warburg and Otto Meyer-hof, Lipmann was the deepest thinking, most clear-sighted, and creative of the architects of biochemistry in its construction phase, laying the foundations of metabolic enzymology. Trained in both medicine and chemistry, he combined these two areas of bioscientific research, both by experimental skill and artistic intuition. He formed a great international school of pupils and disciples, whom he led into new fields and left to develop as he turned to plow new ground. His primary interest lay in the physiological use of organic bound phosphate and the turnover of metabolic energy by its utilization (as “energy rich” or “squiggle” phosphate: ~P) in carbohydrate, fatty acid, amino acid, and nucleic acid syntheses as well as degradations. In this course he discovered the coenzyme of enzymatic transacetylations, coenzyme A, acronymized “CoA” or “CoA-SH,” containing the transfer catalyzing thiol(SH)-function of its pantetheine moiety, a vitamin composed of pantothenic acid and cysteamine. He also initiated research on the nonribosomal synthesis of linear and cyclic (antibiotic) peptides by specifically arranged multienzyme complexes with pantetheine at its active center and on the milieu dependence of the chemical phosphate potential of phosphorylated amino acids in phosphoproteins.
For the discovery of coenzyme A as cocatalyst of the metabolic transfer of activated acetate-groups he received the Nobel Prize for Physiology or Medicine in 1953, jointly with Hans Adolf Krebs, who was laureated for untangling the energy-yielding tricarboxylic acid (or “Krebs”) cycle, which also (re)utilizes CoA-activated acetate, derived from glucose-borne pyruvate.
Curriculum Vitae and Personality . Lipmann was born in Königsberg, East Prussia, on 12 June 1899, the second son of the lawyer Leopold Lipmann and Gertrud Lachmanski. His brother was Heinz Erich Lipmann, playwright, actor, and theater manager at Leopold Jessner’s Berlin Staatstheater. In 1931 Lipmann married Elfreda (Freda) M. Hall, a distinguished artist, photographer, and fashion designer. Their son, Steven Hall Lipmann, became a professor of comparative literature in Boston, Massachusetts.
Lipmann came from a typical liberal German-Jewish middle-class family in which general education, arts, and social engagement were de rigueur, while religion was less important. Besides life sciences, he also loved life per se and beauty. Though a serious student, he was broadly interested, though not active, in theatrical and modern art. He interrupted his medical studies in Königsberg in 1921 and spent one semester in Munich’s Schwabing district with his brother, and a second semester in Berlin to enjoy the postwar Roaring Twenties with its masqued balls, world-renowned stage performances, and theaters. In Berlin he met his future wife, a practicing artist, and he soon used the pretext of learning new scientific methods to return from Heidelberg again to Berlin.
Lipmann’s research combined originality with critical strictness and an impressive ability to extrapolate into the “right,” experimentally approachable, chemical and biological direction to uncover metabolic pathways. He had an almost intuitive ability to see the “possible.” The leitmotif of his work was the enzymatic utilization of chemical-bond-energy from degradation of foodstuffs (essentially, glucose from glycolysis) for the biosynthetic processes involving phosphates and vitamin-derived coenzymes, leading to condensed biomacromolecules such as proteins, nucleic acids, fats, and their conjugates.
Lipmann’s experiments were simple, yet well conceived and to the point. His methods remained those of his training: Warburg respirometry; test-tube incubations, fractionations, and separations by all current methods; (spectro)photometry; and slide-rule. He saw technical progress in methodology and data collecting as necessary for accumulating verifiable and falsifiable evidence, not as means per se. He dared extrapolations but rarely over-stressed the results, using them instead to suggest further investigations.
After his training at Berlin and Heidelberg in the collegial team of independent junior research workers under Otto Meyerhof’s steering synthetic and Karl Lohmann’s bridling analytic supervision, he started on his own at Boston’s Massachusetts General Hospital, where he quickly developed his intrinsic leadership qualities. He was brains but not boss. Private frank discussions in small circles on writing reports and papers, common seminars, and coffee hours were the fruitful ground for continuing branching and diversification, even when international fame increased the momentum.
After receiving a classical education in the local humanistic gymnasium, Lipmann studied medicine (1917–1923), influenced by his Lachmanski uncle, an admired pediatrician. He also studied chemistry with the inspiring Hans Leberecht Meerwein, first at the University of Königsberg, then at Munich and Berlin. His studies were interrupted by military service in the medical corps at the Marne front and during the influenza epidemic of 1918–1919, and by a research fellowship with Ernst Laqueur of the University of Amsterdam in 1923. He received an MD in 1924 from Berlin University with Peter Rona, who trained many of the later specialists in enzymology, and in 1928 a PhD in chemistry with Meyerhof, under the formal aegis of the well-known biochemist Carl Neuberg from Technische Hochschule Berlin, investigator of yeast fermentation.
Between 1931 and 1939, Lipmann became research assistant to Meyerhof, at the Kaiser Wilhelm Institute (KWI) for Medical Research, Berlin and Heidelberg; to Albert Fischer, at the KWI for Biology, Berlin, cell culture division; as Rockefeller Fellow to Phoebus A. T. Levene at the Rockefeller Institute for Medical Research, New York, New York; and again to Fischer, at the Biological Institute
of the Carlsberg Foundation, Copenhagen. In 1933, when Adolf Hitler seized power in Germany and his government introduced the anti-Semitic race laws, Lipmann remained in Denmark, now supported by the Rockefeller Foundation, to find a place. He emigrated in 1939 to the United States, where he was naturalized in 1944. He served as research associate with Vincent du Vigneaud at Cornell University School of Medicine in New York City (1939–1941), then as a member of the staff at Massachusetts General Hospital, Harvard School of Medicine, in Boston, Massachusetts, first as a research fellow, later as an associate and professor in biological chemistry (1941– 1957). In 1957 Lipmann was appointed (emeritus) professor of biochemistry at the Rockefeller Institute of Medical Research, Rockefeller University, New York City. He died in Poughkeepsie (not far from his country home in Rhinebeck, New York) on 24 July 1986.
Lipmann was multiply recognized by honorary academic degrees: MD, University of Marseilles (1942) and University of Copenhagen (1953); MA, Harvard University (1949); DSc, University of Chicago (1953), University of Paris (1966), Harvard University (1967), and Rockefeller University (1971); LHD, Brandeis University Waltham (1954) and Yeshiva University (1964). In 1953 he received the Nobel Prize in Physiology or Medicine; in 1948 both the Mead Johnson Award and the Carl Neuberg Medal; in 1966 the National Medal of Science; and in 1975 the Pour le Mérite (German order of merit).
Lipmann was an elected or honorary member of almost all major academies of science worldwide, including the Danish Royal Academy of Sciences and the New York Academy of Sciences (1949); the U.S. National Academy of Sciences (1950); the American Philosophical Society (1959); the Royal Society of London (1962); and the German Academy of Sciences Leopoldina (1969); as well as many bioscientific societies.
Lipmann stands in the hub of the wheel of evolving metabolic molecular biology. His peers were school-forming colleagues of the Meyerhof-Lohmann team, among others: Severo Ochoa, David Nachmansohn, Karl Mayer, and Dean Burk; his pupils came from all over the world and spread internationally, forming the nuclei of new schools of experiment and thought in the chemical and medical biosciences.
Scientific Achievements . During his medical and post-clinical training on the ward and at the section table, Lipmann developed scruples on the material aspects of the vocation but also on his avocation as a general or specialized practitioner. He wanted a more scientific understanding of the processes he observed. Having understood early on how essentially interwoven chemical and life processes are, he completed, parallel to his studies in medicine, additional time-consuming courses at the teacher’s level in general and analytical chemistry and also passed the Staatsexamen (teacher’s examination), which would allow him to work in the Prussian school service if need arose.
Energy Cycles Involving Phosphocreatine . Luckily, he followed the scientific career instead. Part of his medical practical year in Berlin he spent with Ludwig Pick in pathology, the other part on the famous three-months training course in quantitative physical methods of then-modern colloid chemistry at Leonor Michaelis’s and Peter Rona’s research laboratory. There he met some of his later peers in the nascent biochemical sciences. The quarter of a year studying the ion dependency of colloidal ferric hydroxyde sols as model of proteins sufficed for obtaining the MD from inflation-stricken Berlin University, followed by six months of laboratory practice in affluent Amsterdam. Thus trained practically and prepared mentally for research in enzymology and intermediary metabolism, Lipmann chose to study biochemistry at one of the foremost places in Germany: Meyerhof’s laboratory at Warburg’s section of the KWI for Biology in Berlin-Dahlem.
The focus of interest of biochemists at that time when cell-free systems opened for detailed enzyme studies were the glycolytic processes in yeast during alcoholic fermentation (glucose yielding 2 moles each of ethanol and CO2plus energy) and in muscle during work (glucose yielding 2 moles of lactate plus energy), in both of which phosphate is involved. Meyerhof and Archibald V. Hill had just received the Nobel Prize in Physiology or Medicine (1922) for their studies on the energetic stoichiometry in muscle contraction. Lohmann and Meyerhof had demonstrated that the two processes run parallel except for the last step, when pyruvate is either reduced (in muscle) to lactic acid or split (in yeast) to CO2 and acetalde-hyde followed by reduction to ethanol. Both reductions use pyridine nucleotide (NAD+) as a hydrogen carrier. It was postulated that lactic acid causes muscular contraction. It became clear that energy production and intermediary metabolism are mechanistically, that is, chemically, connected.
This new concept struck Lipmann, and he applied for and was accepted into Meyerhof’s select research group to work on his PhD thesis in chemistry. This resulted in important studies: (1) on creatine phosphate as energy store, and (2) on interconnected metabolic effects of fluoride on glycolysis, respiration, and oxidized hemoglobin. Despite being rather preliminary, they formed the basis for later fundamental insights. When Einar Lundsgaard showed in 1930 that iodoacetate (or fluoride) poisoning of muscle does not block contraction, which goes on until creatine phosphate stores are exhausted, it became clear that the latter, not the acidification, is the prime energy donor in working muscle. By manometrically following the primary breakdown of creatine phosphate and the secondary formation of lactate during electrostimulation of (frog) muscle, Lipmann and Meyerhof proved this definitely. Lohmann showed calorimetrically the energy equivalency of creatine phosphate and the “energy rich” end-(or “seven minute”)-phosphate of his newly discovered adenosine triphosphate (ATP). Gustav Embden stated that hexose-diphosphates, the initiating phosphorylated intermediates in glycolysis, are split between carbon #3 and #4 in the middle of the six-carbon chain of the hexose sugar to two molecules of acid-stable triosephosphate via instable phosphorylated derivatives, and set the keystone on the arch of the “EmbdenMeyerhof” glycolytic cycle.
Now everything fell into place: “Energy rich” phosphate intermediates of glycolysis, phosphoglycerylphosphate (PGA) and phosphoenolpyruvate (PEP), transfer enzymatically the active phosphate group to adenosine diphosphate (ADP) to form ATP, which then is either used directly for all energy-driven cellular processes or intermediarily phosphorylates creatinine to creatine phosphate as energy buffer and store while regenerating ADP
for further transphosphorylation cycles. ATP, formed by electron withdrawing (oxidative) enzymatic processes, is used as the universal energy source to drive chemical work in metabolism as well as mechanical work in muscle, as schematized in Figure 1.
Concept of the “Energy Rich Bond” in Biochemical Systems . This became the origin of the concept of “energy rich” or “squiggle” (~) bonds as the site of the event in group transfer reactions. Biochemists took up the concept enthusiastically, as it gave them a feeling for the potential or pressure inherent in the event, while physicochemists remained skeptical about the “loose speak” of the non-initiated. Nevertheless, it is a useful and suggestive symbol for a molecule in a special quantum chemical conformation of its binding system. Lipmann introduced the concept into scientific discussion in his groundbreaking 1941 review article, “Metabolic Generation and Utilization of Phosphate Bond Energy,” in the first volume of Advances in Enzymology and Related Areas of Molecular Biology.
The ~ symbolizes the chemical bond between carrier (C) and donor (D) moieties from electron (e-) or proton (H+) to groups (for example, phosphate, P) and larger functional portions of a substrate in a transfer system to an acceptor (A): C~D + A A-D + C + [-G°]. G° is the Gibbs Free Energy (reversible work [enthalpy] plus entropy), measured in energy units (kcal or kJ). The value of –G° denotes the energy gradient between the left and right side of the equation. The minus (–) sign in biochemistry is a signature for a downhill reaction. Conventionally, values > –7 kcal (c. 28 kJ) are termed “energy rich.” In a freely reversible (equilibrium) system the (G°s of both sides cancel each other.
When new techniques became available—such as working with tissue culture of whole cells, which he learned from and with Fischer in Berlin and
Copenhagen—Lipmann turned to the study of aerobic glycolysis in chicken heart fibroblasts and other blasts and in embryonic cells, which yielded much more energy than the anaerobic process. He combined it with the manometry of Warburg, who had discovered the large aerobic metabolism in malignant tissue. He replaced cell counting by quantitative metabolic parameters such as respiratory O2 uptake and its dependence on phosphate binding. He measured the aerobic repression of the wasteful energy supply by glycolysis through the highly economical respiratory energy production, what Warburg termed the “Pasteur effect,” and found it similar in normal cultured cells. It was surmised to depend on the redox potential, measurable by dye-indicators: Titratable sulfhydryl (SH) groups of glutathione or SH-enzymes (actually, glyceraldehydephosphate-dehydrogenase, GAPDH) disappeared coincident with glycolysis. This was an early hint to the metabolic formation of “energy-rich phosphate (~P)” bonds that finally lead to the high-energy intermediates of glycolysis by the GAPDH twin-system and by PEP-kinase. We now know that the true Pasteur effect is attributable to a feedback loop by high levels of ATP on phosphofructokinase, phosphorylating fructose-6-phosphate to fructose-1, 6-bisphosphate. But it was at that time that Lipmann became interested in the role of organic phosphates in metabolism.
Pyruvic Acid Oxidation, Activated Phosphate and Acetate, Coenzyme . A . Cell-free extracts of Lactobacillus delbrueckii require inorganic phosphate (Pi) for oxidation of the glycolysis intermediate pyruvic acid and yield ATP with added adenylic acid (AMP). As Lipmann and L. Constance Tuttle showed in 1944, the phosphoroclastic reaction of pyruvate is reversible; pyruvate and P i can be replaced by acetyl phosphate, or, as observed soon with a fractionated enzyme system, by pyruvate decarboxylase, the electron carrier nicotine adenine dinucleotide (NAD+) and transacetylase plus a heat stable coenzyme—also found by David Nachmansohn in New York, and by Wilhelm Feldberg in Cambridge, England, as cofactor in the acetylation of choline for the synthesis of the neurotransmitter acetyl choline—that Lipmann named coenzyme A (CoA) and identified as a general carrier in transacetylations.
In combined work with Esmond E. Snell and other biochemists, it was found that CoA is an unusually complex molecule, consisting of phosphorylated adenylic acid and pantetheine phosphate (phosphate ester of the vitamin pantothenic acid peptidically bound to mercaptoethylamine) joined by a diphosphate bridge (shown in Figure 2). Soon after, Feodor Lynen and Ernestine Reichert found that the acetic acid in acetyl-CoA is bound as thermodynamically “energy rich” thioester or acylthiol to the activating acidic SH-terminus, thus S-acetyl-CoA = CoA-S-COCH3.
As a kinetically stable, thermodynamically labile, transport metabolite, acetyl-CoA has multiple functions in energy transfer in all known organisms. In the metabolism of carbohydrates, fats, sterols, and proteins it is an intermediary of enzymatic cellular condensing reactions, for example, in the Krebs citric acid cycle and in the Lynen fatty acid forming and degrading spirals. S-acetyl-CoA is energetically similar and mechanistically comparable to acetylchloride used in organic syntheses, also an acid anhydride. The principle of group activation was verified in carbamoyl phosphate generation (in urea and pyrimidine syntheses) and sulfate activations (to chondroitins, cerebrosides, or tyrosines in proteins).
Protein Biosynthesis and Molecular Evolution . Group activation is also the basis of peptide bond formation in the biosynthesis of proteins and, in general, of polycondensations (of sugars, nucleic acids, lipids, and esters). Amino acids are ATP-activated by phosphorylation of their carboxyl group, then, as postulated early (1950) by the cytobiologist Daniel Mazia, transferred to RNA-carriers with amino acid–specific triplet marks and
brought into the proper sequence by means of the anti-codons of messengers that are blots of informing DNAs of the genome. The machinery is in the ribosomes, as first shown in 1955 by Philip Siekevitz in the team of Paul C. Zamecnik and Mahlon B. Hoagland at Harvard University working with microsomal cell fractions of liver and bacteria. Lipmann used the latter system. The mechanism of bacterial polypeptide synthesis runs in three phases, as shown in Figure 3: (1) initiation; (2) polymerization; and (3) termination. The elongation factors (unstable Tu, stable Ts, and G) were separated and their function at the acceptor (A) site and donor (D) site of the ribosome complex in the ribosomal peptide bond established. This forms the basis of the present understanding of the whole process of protein biosynthesis, which is mechanistically analogous, yet not materially homologous, in eukaryotes.
Phosphoproteins and Site-Dependent Increase of Phosphorylation Potential of Serine- and Tyrosine-O-Phosphates . Phosphoproteins as nutritional phosphate carriers are found in milk casein (3% P) and in egg yolk vitellinic acid (10% P). P is O-bound to serine and/or tyrosine residues of the polypeptides, and most of it is relatively acid-stable. Phosphorylated proteins had interested Lipmann during his work at Phoebus Levene’s laboratory in 1932 and remained in his subconscious for more than thirty years. Then the transphosphorylations from and to proteins came into focus, and he again turned to them. He showed that the phosphate groups of serine and tyrosine sites have different thermodynamic potential and are turned over from and to ATP by specific protein kinases at different speed. The ATP-dependent protein kinases act partially reversible (as shown with phosvitin or immunoglobulins), so that ADP may be upphosphorylated to ATP by certain clustered protein phosphate groups within the sequence if a strong pull is applied. This means that in such serine or tyrosine clusters the otherwise very stable phosphate becomes energy rich and may be transferred between donors and acceptors by protein transphosphorylations in receptor functions and cell-regulatory signal chains. This is essentially the basis for the inter- and intracellular communication by protein factors and chemical messages.
Polypeptide Antibiotics on Nonribosomal Templates by Thiol-Linked Peptide Activation and Polymerization . In addition to the peptide bond formation by the ribosomal apparatus, peptides are also formed in special cases and for special vital purposes by nonribosomal multienzyme complexes, which may have evolved earlier from the chain of events in fatty acid ana- and catabolism. Early on, Lipmann became aware of such energy-utilizing processes as exemplified by glutathione and gramicidin biosyntheses.
Bacilli synthesize straight chain and cyclic antibiotic peptides, often containing a D-amino acid or other fitting molecules. The catalyzing binary enzyme complexes resemble in certain aspects the crank-wheel mechanism of fatty acid syntheses, with pantetheine in the activating, transporting, and assembling center. The first step is the ATP-activation of L-phenylalanine by the small aminoacyl carrier protein; followed by the transfer of the activated amino acid to the central SH-group of the big polyenzyme, which also contains a racemase forming the D-stereomer of the initiating amino acid; and the poly-condensation of more amino acids according to the given pattern of the subunits with or without head-to-tail cyclization to form the loop or cycle, respectively. This basic type can be experimentally, combinatorially, and genetically varied to great applicable extent.
The volume edited by Horst Kleinkauf, Hans von Döhren, and Lothar Jaenicke, The Roots of Modern Biochemistry, contains Lipmann’s complete bibliography.
WORKS BY LIPMANN
“Metabolic Generation and Utilization of Phosphate Bond Energy.” Advanced Enzymology 1 (1941): 99–162.
Wanderings of a Biochemist. New York: Wiley-Interscience, 1971.
“A Long Life in Times of Great Upheaval.” Annual Review of Biochemistry 53 (1984): 1–33.
Duve, Christian de. “Fritz Lipmann: In Memoriam.” FASEB Journal 1 (1987): 1–3.
Jaenicke, Lothar. “Zum Goldenen Nobel Jubiläum.” BIOspektrum 10 (2004): 170–173.
Kalckar, Herman M. “Lipmann and the ‘Squiggle.’” In Current Aspects of Biochemical Energetics: Fritz Lipmann Dedicatory Volume, edited by Nathan Oram Kaplan and Eugene P. Kennedy, 1–9. New York: Academic Press, 1966.
Kleinkauf, Horst, Hans von Döhren, and Lothar Jaenicke, eds. The Roots of Modern Biochemistry: Fritz Lipmann’s Squiggle and Its Consequences. Berlin: Walter de Gruyter, 1988. Also contains Lipmann’s complete bibliography.
Levitan, Thomas N. Laureates: Jewish Winners of the Nobel Prize. 1960.
Medawar, Jean, and David Pyke. Hitler’s Gift: The True Story of the Scientists Expelled by the Nazi Regime. New York: Arcade, 2001.
Nachmansohn, David. German-Jewish Pioneers in Science, 1900–1933: Highlights in Atomic Physics, Chemistry, and Biochemistry. Berlin: Springer-Verlag, 1979.
Organizer. “The Mechanisms of Protein Synthesis.” CSH Symposia on Quantitative Biology 34 (1969): vii.
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Lipmann, Fritz Albert
Fritz Albert Lipmann, 1899–1986, American biochemist, b. Germany, grad. Univ. of Berlin (M.D., 1922; Ph.D., 1927). He emigrated to the United States in 1939 and became a citizen in 1944. In 1941 he became research chemist at Massachusetts General Hospital, Boston, and in 1949 professor of biochemistry at Harvard medical school. For his discovery of coenzyme A, a crucial intermediary in carbohydrate oxidation, he was awarded jointly with H. A. Krebs the 1953 Nobel Prize in Physiology or Medicine.
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Lipmann, Fritz Albert
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