Jan-Hendrik S. Hofmeyr

Last updated

Jan-Hendrik Hofmeyr
Born
Jan-Hendrik Servaas Hofmeyr

(1953-08-25) 25 August 1953 (age 70)
Durban, South Africa
NationalitySouth African
Alma mater Stellenbosch University
Known formetabolic control analysis, metabolic regulation
Awards Harry Oppenheimer Fellowship Award and Gold Medal (2002)
Beckman Coulter Gold Medal of the South African Society for Biochemistry and Molecular Biology (2003)
Scientific career
Fields Biochemistry
Institutions Stellenbosch University
Thesis Studies in steady-state modelling and control analysis of metabolic systems  (1986)

Jan-Hendrik Hofmeyr FRSSAf [1] (born 25 August 1953) is one of the leaders in the field of metabolic control analysis and the quantitative analysis of metabolic regulation.

Contents

Education

Hofmeyr was born in Durban, South Africa. He obtained BSc hons. (1976), MSc (1978) and PhD (1986) at the University of Stellenbosch. While preparing his doctoral thesis he spent six months with Athel Cornish-Bowden at Birmingham and three months with Henrik Kacser at Edinburgh. Both of these visits led to long-term collaborations. [2] [3] [4]

Research

Hofmeyr's doctoral research concerned the use of graphical patterns to elucidate chains of interaction in metabolic regulation, later published in the European Journal of Biochemistry, [5] and his collaboration with Kacser led to a study of the effect of moiety-conservation on control of pathways. [6] At this time he and Cornish-Bowden were concerned that the development of metabolic control analysis seemed to be almost independent of the knowledge of metabolic regulation that had grown from the recognition of regulatory mechanisms in the 1950s and 1960s, most notably the importance of feedback inhibition [7] [8] [9] [10] and cooperative behaviour of enzymes. [11] This led them to propose a way of quantifying metabolic regulation, [12] the first of a series of publications that culminated in an analysis of the role of supply and demand in biochemical systems, i.e. an analysis of how negative feedback allow metabolic pathways to respond to changes in the demand for metabolites while resisting variations in the supply of starting materials. [13]

During the 21st century Hofmeyr has applied ideas of control analysis to ecosystems, [14] and to the understanding of the self-organization of cell function in the spirit of Robert Rosen. [15] More recently he has worked on the development of code biology, the novel discipline founded by Marcello Barbieri that recognizes that the genetic code is just one of several codes used and needed by biological systems. [16]

Career

Appointed as Junior Lecturer in the Biochemistry Department of the University of Stellenbosch in 1975, Hofmeyr eventually became Distinguished Professor in 2014, and Emeritus Professor in 2019. Between 2009 and 2015 he was Co-director and then Director of the Centre for Studies in Complexity at Stellenbosch, which he had co-founded in 2009. [3] [17]

Prizes and distinctions

Other activities

In addition to his scientific research, Hofmeyr is a classically trained flute player and also plays the baroque flute, guitar and banjo. He was one of the composers and performers who helped launch the Afrikaans "Kabaret" tradition in the 1980s in South Africa, through his work with authors, composers and directors. His classic scores for lyrics of Hennie Aucamp and Etienne van Heerden have become standard items in Afrikaans popular music. He has also played older characters in productions of the University of Stellenbosch Drama Department. [20]

Related Research Articles

<span class="mw-page-title-main">Enzyme</span> Large biological molecule that acts as a catalyst

Enzymes are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called enzymology and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties.

<span class="mw-page-title-main">Nicotinamide adenine dinucleotide</span> Chemical compound which is reduced and oxidized

Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine nucleobase and the other, nicotinamide. NAD exists in two forms: an oxidized and reduced form, abbreviated as NAD+ and NADH (H for hydrogen), respectively.

<span class="mw-page-title-main">Mevalonate pathway</span> Series of interconnected biochemical reactions

The mevalonate pathway, also known as the isoprenoid pathway or HMG-CoA reductase pathway is an essential metabolic pathway present in eukaryotes, archaea, and some bacteria. The pathway produces two five-carbon building blocks called isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), which are used to make isoprenoids, a diverse class of over 30,000 biomolecules such as cholesterol, vitamin K, coenzyme Q10, and all steroid hormones.

<span class="mw-page-title-main">Henrik Kacser</span> Hungarian biochemist and geneticist

Henrik Kacser FRSE was a Austro-Hungarian-born biochemist and geneticist who worked in Britain in the 20th century. Kacser's achievements have been recognised by his election to the Royal Society of Edinburgh in 1990, by an honorary doctorate of the University of Bordeaux II in 1993.

<span class="mw-page-title-main">Hans Westerhoff</span> Dutch biologist and biochemist (born 1953)

Hans Victor Westerhoff is a Dutch biologist and biochemist who is professor of synthetic systems biology at the University of Amsterdam and AstraZeneca professor of systems biology at the University of Manchester. Currently he is a Chair of AstraZeneca and a director of the Manchester Centre for Integrative Systems Biology.


Arthur Beck Pardee was an American biochemist. One biographical portrait begins "Among the titans of science, Arthur Pardee is especially intriguing." There is hardly a field of molecular biology that is not affected by his work, which has advanced our understanding through theoretical predictions followed by insightful experiments. He is perhaps most famous for his part in the 'PaJaMo experiment' of the late 1950s, which greatly helped in the discovery of messenger RNA. He is also well known as the discoverer of the restriction point, in which a cell commits itself to certain cell cycle events during the G1 cycle. He did a great deal of work on tumor growth and regulation, with a particular focus on the role of estrogen in hormone-responsive tumors. He is also well known for the development of various biochemical research techniques, most notably the differential display methodology, which is used in examining the activation of genes in cells. More recently he championed the acceptance and adoption of the conceptual review as a valuable approach to unearthing new knowledge from the enormous stores of information in the scientific literature. He died in February 2019 at the age of 97.

<span class="mw-page-title-main">Purine nucleoside phosphorylase</span> Enzyme

Purine nucleoside phosphorylase, PNP, PNPase or inosine phosphorylase is an enzyme that in humans is encoded by the NP gene. It catalyzes the chemical reaction

<span class="mw-page-title-main">Metabolic control analysis</span> Metabolic control

Metabolic control analysis (MCA) is a mathematical framework for describing metabolic, signaling, and genetic pathways. MCA quantifies how variables, such as fluxes and species concentrations, depend on network parameters. In particular, it is able to describe how network-dependent properties, called control coefficients, depend on local properties called elasticities or Elasticity Coefficients.

<span class="mw-page-title-main">Reinhart Heinrich</span> German biophysicist

Reinhart Heinrich was a German biophysicist.

Metabolite channeling is the passing of the intermediary metabolic product of one enzyme directly to another enzyme or active site without its release into solution. When several consecutive enzymes of a metabolic pathway channel substrates between themselves, this is called a metabolon. Channeling can make a metabolic pathway more rapid and efficient than it would be if the enzymes were randomly distributed in the cytosol, or prevent the release of unstable intermediates. It can also protect an intermediate from being consumed by competing reactions catalyzed by other enzymes.

<span class="mw-page-title-main">Committed step</span> Step in enzymatic chemical reactions

In enzymology, the committed step is an effectively irreversible enzymatic reaction that occurs at a branch point during the biosynthesis of some molecules. As the name implies, after this step, the molecules are "committed" to the pathway and will ultimately end up in the pathway's final product. The first committed step should not be confused with the rate-limiting step, which is the step with the highest flux control coefficient. It is rare that the first committed step is in fact the rate-determining step.

<span class="mw-page-title-main">Stefan Schuster</span> German biophysicist

Stefan Schuster is a German biophysicist. He is professor for bioinformatics at the University of Jena.

David A. Fell is a British biochemist and professor of systems biology at Oxford Brookes University. He has published over 200 publications, including a textbook on Understanding the control of metabolism in 1996.

<span class="mw-page-title-main">Athel Cornish-Bowden</span> British biochemist

Athel Cornish-Bowden is a British biochemist known for his numerous textbooks, particularly those on enzyme kinetics and his work on metabolic control analysis.

Harold Edwin Umbarger was an American bacteriologist and biochemist.

<span class="mw-page-title-main">Zacharias Dische</span> American biochemist (1895–1988)

Zacharias Dische was an American biochemist of Ukrainian-Jewish origin. He worked as a biochemical researcher in Vienna before being forced by the Anschluss to become a refugee, first in France and then in the US, where he joined the faculty of Columbia University in 1943. During his time in Marseilles he made a major discovery that is little known and usually attributed to others.

Herbert M. Sauro is a Welsh biochemist who works in the field of metabolic control analysis and systems biology.

In biochemistry, a rate-limiting step is a step that controls the rate of a series of biochemical reactions. The statement is, however, a misunderstanding of how a sequence of enzyme catalyzed reaction steps operate. Rather than a single step controlling the rate, it has been discovered that multiple steps control the rate. Moreover, each controlling step controls the rate to varying degrees.

Daniel Edward Atkinson was an American biochemist who worked at UCLA for 40 years from 1952 until his retirement in 1992, though he continued his scientific work as Emeritus Professor. He is best known for the concept of energy charge.

In metabolic control analysis, a variety of theorems have been discovered and discussed in the literature. The most well known of these are flux and concentration control coefficient summation relationships. These theorems are the result of the stoichiometric structure and mass conservation properties of biochemical networks. Equivalent theorems have not been found, for example, in electrical or economic systems.

References

  1. ↑ "Current Fellows – Royal Society of South Africa". Royal Society of South Africa . 5 October 2021. Retrieved 27 May 2022.
  2. ↑ "Jannie Hofmeyr CV" (PDF). University of Stellenbosch. 2019. Retrieved 27 May 2022.
  3. 1 2 "Hofmeyr, Jan-Hendrik Servaas (Jannie)". African Scientists Directory. Retrieved 27 May 2022.
  4. 1 2 "The Oppenheimer Memorial Trust | 2002 — Jan-Hendrik Hofmeyr". Oppenheimer Memorial Trust. 2022. Retrieved 27 May 2022.
  5. ↑ Hofmeyr, J.-H. S. (1989). "Control-pattern analysis of metabolic pathways: Flux and concentration control in linear pathways". Eur. J. Biochem. 186 (1–2): 343–354. doi: 10.1111/j.1432-1033.1989.tb15215.x . PMID   2598934.
  6. ↑ Hofmeyr, J.-H. S.; Kacser, H.; Van der Merwe, K.J. (1986). "Metabolic control analysis of moiety-conserved cycles". Eur. J. Biochem. 155 (3): 631–641. doi: 10.1111/j.1432-1033.1986.tb09534.x . PMID   3956502.
  7. ↑ Dische, Z. (1941). "Sur l'interdépendance des divers enzymes du système glycolytique et sur la régulation automatique de leur activité dans les cellules" [On the interdependence of the various enzymes of the glycolytic system and on the automatic regulation of their activity in cells]. Bull. Soc. Chim. Biol. 23: 1140–1148.
  8. ↑ Umbarger, H. E. (1956). "Evidence for a negative-feedback mechanism in the biosynthesis of isoleucine". Science. 123 (3202): 848. Bibcode:1956Sci...123..848U. doi:10.1126/science.123.3202.848. PMID   13324101.
  9. ↑ Yates, R. A.; Pardee, A. B. (1956). "Control of pyrimidine biosynthesis in Escherichia coli by a feed-back mechanism". J. Biol. Chem. 221 (1–2): 757–770. doi: 10.1016/S0021-9258(18)65188-9 .
  10. ↑ The discovery of feedback inhibition of enzymes is usually attributed to the two papers of 1956. However, it was actually discovered much earlier by Zacharias Dische: see Cornish-Bowden, A. (2021). "Zacharias Dische and the discovery of feedback inhibition: A landmark paper published in the forerunner of Biochimie". Biochimie. 182: 120–130. doi:10.1016/j.biochi.2020.11.013. PMID   33285219. S2CID   227948364.
  11. ↑ Monod, J.; Changeux, J.P.; Jacob, F. (1963). "Allosteric Proteins and Cellular Control Systems". J. Mol. Biol. 6 (4): 306–329. doi:10.1016/s0022-2836(63)80091-1. PMID   13936070.
  12. ↑ Hofmeyr, J.-H. S.; Cornish-Bowden, A. (1991). "Quantitative assessment of regulation in metabolic systems". Eur. J. Biochem. 200 (1): 223–236. doi: 10.1111/j.1432-1033.1991.tb21071.x . PMID   1879427.
  13. ↑ Hofmeyr, J.-H. S.; Cornish-Bowden, A. (2000). "Regulating the cellular economy of supply and demand". FEBS Lett. 476 (1–2): 47–51. Bibcode:2000FEBSL.476...47H. doi: 10.1016/S0014-5793(00)01668-9 . PMID   10878248.
  14. ↑ Getz, W.M.; Westerhoff, H.V.; Hofmeyr, J.-H. S.; Snoep, J.L (2003). "Control analysis of trophic chains". Ecological Modelling. 168 (1–2): 153–171. Bibcode:2003EcMod.168..153G. doi:10.1016/S0304-3800(03)00208-4.
  15. ↑ Wolkenhauer, O.; Hofmeyr, J.-H. S. (2007). "An abstract cell model that describes the self-organization of cell function in living systems". J. Theor. Biol. 246 (3): 461–476. Bibcode:2007JThBi.246..461W. doi:10.1016/j.jtbi.2007.01.005. PMID   17328919.
  16. ↑ Hofmeyr, J.-H. S. (2018). "Causation, Constructors and Codes". BioSystems. 164 (SI): 121–127. Bibcode:2018BiSys.164..121H. doi:10.1016/j.biosystems.2017.09.008. PMID   28916462.
  17. ↑ "Stellenbosch Institute for Advanced Study: Understanding complexity" . Retrieved 10 March 2021.
  18. ↑ "The South African Society of Biochemistry and Molecular Biology: SASBMB medals" . Retrieved 10 March 2021.
  19. ↑ "Die Akademie / Akademiepryse 1909-" (in Afrikaans). Suid-Afrikaanse Akademie vir Wetenskap en Kuns. 2 July 2015. Archived from the original on 2 July 2015. Retrieved 27 May 2022.
  20. ↑ "University of Stellenbosch Drama Department" . Retrieved 10 March 2021.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.