Daniel Atkinson (biochemist)

Atkinson was an undergraduate at the University of Nebraska, and obtained a Ph.D. at Iowa State University, where he investigated the synthesis of aromatic amino acids{{cite journal | doi= 10.1016/0003-9861(51)90208-1 | journal = Arch. Biochem. Biophys. | last1 = Atkinson | first1 = D. E. | last2 = Fox | first2 = S. W. | title = Synthesis of aromatic amino acids by mutant strains of Lactobacillus arabinosus | year = 1951 | volume = 31 | number = 2 | pages = 212–223| pmid = 14830228 }} and effects of p-fluorophenylalanine{{cite journal | title = Effects of p-fluorophenylalanine on the growth of Lactobacillus arabinosus | journal = Arch. Biochem. Biophys. |year = 1951 |volume =31 | number = 2 | doi = 10.1016/0003-9861(51)90207-X | pages = 205–211 | last1 = Atkinson | first1 = D. E. | last3 = Fox | first3 = S. W. | last2 = Melvin| first2 = S.| pmid = 14830227 }} in Lactobacillus arabinosus, under the supervision of Sidney Fox.

After a post-doctoral period at the California Institute of Technology, followed by one as a research scientist at Argonne National laboratories, Atkinson moved to UCLA in 1952 as the second biochemist in the department. In his first work at UCLA he studied the bacterium Hydrogenomonas facilis, beginning with a description of the purification of hydrogenase.{{cite journal | last1 = Atkinson | first1 = D. E. | last2 = McFadden | first2 = B. A. | title = The biochemistry of Hydrogenomonas 1. The hydrogenase of Hydrogenomonas facilis in cell-free preparations | journal = J. Biol. Chem. | volume = 210 | number = 2 | pages = 885–893 | year = 1954| doi = 10.1016/S0021-9258(18)65415-8 | pmid = 13211626 | doi-access = free }}

Atkinson remained at UCLA for the remainder of his career, where he undertook numerous studies of metabolic regulation. Of these the best known is his introduction of the concept of energy charge.

Atkinson and Walton{{cite journal | doi= 10.1016/S0021-9258(17)45240-9| title = Kinetics of regulatory enzymes: Escherichia coli phosphofructokinase | last1 = Atkinson | first1 = D. E. | last2 = Walton | first2 = G. M. | pages = 757–763 | journal = J. Biol. Chem. | volume = 240 | number = 2 | year = 1965 | pmid = 14275132 | doi-access = free }}{{cite journal | title = Adenosine triphosphate conservation in metabolic regulation: Rat liver citrate cleavage enzyme | journal = J. Biol. Chem. | last1 = Atkinson | first1 = D. E. | last2 = Walton | first2 = G. M. | year = 1967 | pages = 3239–3241 | number = 12 | volume = 242| doi = 10.1016/S0021-9258(18)95956-9 | pmid = 6027798 | doi-access = free }} introduced the concept of energy charge, later discussed more fully, as a way to rationalize the dependence of metabolic processes on the proportions of the adenylates. For pairs of metabolites, such as the reduced and oxidized forms of NAD, a straightforward ratio of concentrations is sufficient, but the case of the adenylates is more complicated, as there are three components to be considered, AMP, ADP and ATP.

The three adenylates are related by the reaction catalysed by adenylate kinase:

: ATP + AMP <=> 2 ADP

and on the basis of this equation Atkinson proposed the following ratio as a measure of the metabolic state of a cell:

: $\backslash mathrm\{Energy\}\; \backslash text\{\; \}\; \backslash mathrm\{charge\}\; =\; \backslash frac\{[\backslash mathrm\{ATP\}]\; +\; 0.5[\backslash mathrm\{ADP\}]\}\{[\backslash mathrm\{ATP\}]\; +\; [\backslash mathrm\{ADP\}]\; +\; [\backslash mathrm\{AMP\}]\}$

Atkinson's work on the energy charge was part of a broader interest in metabolic regulation and its mechanisms, and he contributed numerous influential publications in this field. In addition to general articles on metabolic regulation{{cite journal | doi= 10.1126/science.150.3698.851 | journal = Science | last =Atkinson| first = D. E. | title =Biological feedback control at the molecular level | volume = 150 | number =3698 | year =1965 | pages = 851–857| pmid = 5319760 | bibcode = 1965Sci...150..851A }}{{cite journal | doi= 10.1146/annurev.mi.23.100169.000403 | journal = Annu. Rev. Microbiol. | volume = 23 | pages = 47–68| year = 1969| last =Atkinson| first = D. E. | title = Regulation of enzyme function| pmid = 4900062 }} he also worked on specific enzymes, such as isocitrate dehydrogenase{{cite journal | journal = J. Biol. Chem. | volume = 240 | number =6 | last1 =Atkinson| first1 = D. E. | last2 = Hathaway | first2 = J. A. | last3 =Smith | first3 = E. C. | title =Kinetics of regulatory enzymes: Kinetic order of the yeast diphosphopyridine nucleotide isocitrate dehydrogenase reaction and a model for the reaction | pages = 2682–2690 | year = 1965| doi = 10.1016/S0021-9258(18)97380-1 | pmid = 14304886 | doi-access = free }} and glutaminase,{{cite journal | journal = J. Biol. Chem. | volume =264 | number = 26 | pages = 15357–15360 | last1 = Szweda | first1 = L. I.| last2 =Atkinson| first2 = D. E. | title = Response of rat-liver glutaminase to pH: Mediation by phosphate and ammonium ions| year =1989 | doi =10.1016/S0021-9258(19)84835-4 | pmid =2768267 | doi-access =free }} and on the role of urea synthesis in vertebrates.{{cite journal | doi= 10.1086/physzool.65.2.30158252| last1 =Atkinson| first1 = D. E. | journal = Physiol. Zool. | volume = 65 | number = 2 | pages = 243–267 | title = Functional roles of urea synthesis in vertebrates| year =1992| s2cid =87121092}}

Atkinson's influential book on energy metabolism set out the concepts and understanding of metabolic regulation that had developed over the preceding decades (most notably by him), in particular explaining the role of ratios of metabolite concentrations, including the energy charge, in regulating enzyme properties.{{cite book| isbn= 978-0120661503| last = Atkinson | first = Daniel E. | title = Cellular Energy Metabolism and its Regulation | publisher = Academic Press | year = 1977}}

Atkinson spent his last years living in Corvallis, Oregon. He died on February 2, 2024, at the age of 102.

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Category:1921 births

Category:2024 deaths

Category:20th-century American biochemists

Category:American men centenarians

Category:People from Pawnee City, Nebraska