I have a life career-goal of understanding the biochemistry, molecular biology and genetics of the pathway, control and compartmentation of starch biosynthesis in developing cereal grain. I have filed several biotech patent applications and published many papers in this area over many years. I cofounded ExSeed Genetics LLC in 1994 and EnaGen LLC in 2007. The overall aim of our work is to use genetic and biotechnological approaches to improving maize yield, grain quality and yield stability.




PhD (1981)                   Council for National Academic Awards, Surrey University & MRC Toxicology Unit and ICI Central Toxicology Lab., Cheshire, UK.

BSc (1976)                     Applied Biology (Honours), Hertfordshire University, Hatfield, UK.

A&O Levels                   Abbeydale Grammar School, Sheffield, Yorkshire, UK




2007 - Present               Founder and Director, EnaGen LLC, Ames, IA & Chapel Hill, NC, USA.

2000 - 2007                   Unit R&D Director, ExSeed Genetics Research, BASF Plant Science, 2901 South Loop Drive, Bldg3 Suite 3800, Ames, Iowa, USA.

1994 – 2000                  Founder and Research Director, ExSeed Genetics L.L.C., Food Science Building, Iowa State University, Ames, Iowa, USA.

1988 - 1994                   Group Manager, ICI/Zeneca Seeds, Biochemistry, Cytogenetics and Physiology Group, Slater, Iowa, USA.

1986 – 1988                  Project Leader, ICI/Zeneca Seeds, Grain Filling Project, Bioscience Research Laboratory, Runcorn, Cheshire, UK.

1981 - 1986                   Senior Research Scientist & Biochemistry Group Leader, ICI Corporate Bioscience Laboratory, Runcorn, Cheshire, UK.

1976 – 1981                  Research Scientist, ICI Central Toxicology Laboratory, Pulmonary Toxicology Group, Biochemical Mechanisms Section, Alderley Park, Cheshire, UK.


PUBLICATIONS (Book Chapters):

Klucinec J.D. and Keeling P.L. (2006) Genetic modifications of plant starches for food applications. In: Functional Foods & Biotechnology (Vol 165, Food Science and Technology). Ed: Shetty, Paliyath, Pometto and Levin. Taylor & Francis, New York.

Klucinec J.D. and Keeling P.L. (2005) Genetic modifications of plant starches for food applications. In: Food Biotechnology 2nd Edition. Ed: Shetty, Paliyath, Pometto and Levin. Taylor & Francis, New York.

Keeling P.L. (1999) From enzyme activity to flux control: a quest to understand starch deposition in developing cereal grains. In: Plant Carbohydrate Biochemistry. Eds. JA Bryant, MM Burrell and NJ Kruger. BIOS Scientific Publishers, Oxford UK.

Keeling P.L. (1997) Starch Biotechnology: Technical Barriers to Starch Improvement. In: Starch: Structure and Functionality. The Royal Society of Chemistry, London.

Keeling P.L. and Greaves J.A. (1991) Response of corn to temperature stresses and opportunities for breeding and biotechnology. 45th Annual Corn and Sorghum Industry Research Conference. ASTA Annual Meeting. Chicago, US.

Keeling P.L. (1991) The pathway and compartmentation of starch synthesis in developing wheat grain. Invited presentation at the 42nd SEB Conference. Compartmentation of Plant Metabolism in Non-Photosynthetic Tissues. Cambridge University Press.




Denyer, K. and Keeling P.L. (in progress) The functions of the structural domains of starch synthase enzymes. To be submitted. The Plant Journal.

Tziotis A, Seetharaman K, Klucinec JD, Keeling P, White PJ (2005) Functional properties of starch from normal and mutant corn genotypes. Carb Polymers: 61: 238-247.

Gao Z., Guan H. and Keeling P.L. (2004) Involvement of lysine-193 of the conserved “KTGG” motif in the catalysis of maize starch synthase IIa. ABB., 427: 1-7.

Imparl-Radosevich J.M., Gameon, J.R., McKean, A., Wetterberg. D., Keeling P.L. and Guan H. (2003) Understanding catalytic properties and functions of maize starch synthase enzymes. J.Appl.Glycosci., 50: 177-182.

Han, Xian-Zhong, O.H. Campanella, H. Guan, P.L. Keeling and B. Hamaker. (2002) Influence of maize starch granule-associated protein on the rheological properties of starch pastes. Part I. Large deformation measurements of paste properties.  Carbohydrate polymers 49: 315-321.

Han, Xian-Zhong, O.H. Campanella, H. Guan, P.L. Keeling and B. Hamaker. (2002) Influence of maize starch granule-associated protein on the rheological properties of starch pastes. Part II. Dynamic measurements of viscoelastic properties of starch pastes.  Carbohydrate polymers 49: 315-321.

Commuri P.D. and Keeling P.L. (2001) Chain-length specificities of maize starch synthase I enzyme:  studies of glucan affinity and catalytic properties. The Plant Journal 25(5): 475-486.

Nichols D.J., P.L. Keeling, M. Spalding, and H. Guan.  (2000) Involvement of conserved aspartate and glutamate residues in the catalysis and substrate binding of maize starch synthase. Biochemistry 39 (26): 7820-7825.

Wilhelm, E.P., Mullen R.E., Keeling P.L. and Singletary G.W. (1999) Heat stress during grain filling in maize: Effects on kernel growth and metabolism. Crop Science 39: 1733-1741.

Imparl-Radosevich J.M., Keeling P.L. and Guan H. (1999) Essential arginine residues in maize starch synthase IIa are involved in both ADP-glucose and primer binding. FEBS Letters 457: 357-362.

Cao H., Imparl-Radosevich J.M., Guan H., Keeling P.L., James M. and Myers A.M. (1999) Identification of soluble starch synthase activities of maize endosperm. Plant Physiology 120: 205-215.

Imparl-Radosevich J.M., Nichols D.J., Li P., McKean A.L., Keeling P.L. and Guan H. (1999) Characterization of Maize Starch Synthases IIa and  IIb: SS isoforms can be distinguished based on their kinetic properties Arch Biochem Biophys 362: 131-138.

Guan H. and Keeling P.L. (1998) Starch Biosynthesis: Understanding the functions and interactions of multiple isozymes of starch synthase and branching enzyme. Trends in Glycoscience and Glycotechnology 10: 307-319.

Imparl-Radosevich J.M., Li P., Zhang L., McKean A.L., Keeling P.L. and Guan H. (1998) Purification and Characterization of Maize Starch Synthase I and its Truncated Forms Arch Biochem Biophys 353: 64-72

Harn, C., Knight M., Mu, C., Keeling, P.L. and Wasserman, B. P. (1998) Isolation and Characterization of the SS2 Starch Synthase cDNA Clones from Maize Endosperm.  Plant Molec Biol 37: 639-649.

Knight M., Harn, C., Lilley, C.E.R., Guan, H-P., Singletary, G. W., Mu-Forster, C., Wasserman, B.P., and Keeling, P.L. (1998) Molecular cloning of starch synthase I from Zea mays endosperm and expression in E.coli. The Plant Journal. 14: 613-622.

Lu T-J., Jane J_L., and Keeling P.L. (1997) Temperature effect on retrogradation rate and crystalline structure of amylose. Carbohydrate Polymers 33: 19-26.

Guan H-P., Li P., Imparl-Radosevich J., Preiss J. and Keeling P.L. (1997) Comparing the properties of Echerichia coli branching enzyme and maize branching enzyme. Arch Biochem Biophys 342: 92-98.

Singletary G.W., Banisadr R. and Keeling P.L. (1997) Influence of gene dosage on carbohydrate synthesis and enzymatic activities in endosperm of starch-deficient mutants of maize. Plant Physiology 113: 293-304.

Denyer K., Dunlap F. Thorbjornsen T., Keeling P.L., Smith A.M. (1996) The major form of ADP-glucose pyrophosphorylase activity in Maize (Zea Mays L.) endosperm is extra-plastidial. Plant Physiology 112: 779-785.

Ball S., Guan H-P., James M., Myers A., Keeling P.L., Mouille G., Buleon A., Colonna P., and Preiss J. (1996) From glycogen to amylopectin: a model explaining the biogenesis of the plant starch granule. Cell 86: 349-352.

Mu-Forster, C., Huang, R., Powers, J.R., Harriman, R.W., Knight, M., Singletary, G. W., Keeling, P. L. and Wasserman, B. P. (1996) Physical Association of starch biosynthetic enzymes with starch granules of maize endosperm: Granule-associated forms of starch synthase I and starch branching enzyme II.  Plant Physiology 111: 821-829.

Zehr BE, Eckhoff SR, Nyquist WE, and Keeling P.L. (1996) Heritability of product fractions from wet milling and related properties of maize grain. Crop Sci 36: 1159-1165.

Eckhoff SR, Singh SK, Zehr BE, Rausch KD, Fox EJ, Mistry AK, Haken AE, Niu YX, Zou SH, Buriak P, Tumbleson ME and Keeling P.L. (1996) A 100 g laboratory scale corn wet milling procedure. Cereal Chemistry 73: 54-57.

Lu T-J., Jane J_L., Keeling P.L., and Singletary GW. (1996) Effects of ear developmental temperature on maize starch fine structure. Carbohydrate Research 282: 157-170.

Hylton C.M., Denyer K., Keeling P.L., Chang M-T., and Smith A.M. (1996) The effects of waxy mutations on the granule-bound starch synthases of barley and maize endosperms. Planta 198: 230-237.

Zehr BE, Eckhoff SR, Singh SK, and Keeling P.L. (1995) Comparison of wet milling properties among maize inbred lines and their hybrids. Cereal Chemistry 72: 491-497.

Singletary G.W., Banisadr R. and Keeling P.L. (1994). Heat stress during grain filling in maize: Effects on carbohydrate storage and metabolism.  Aust J Pl Physiol. 21 829-841.

Chang M-T., Rimathe D., Becker L., Keeling P.L. and Neuffer M.G. (1994) Characterization of chemical composition of maize defective kernel mutants.  In: Proceedings of SABRAO Seventh International Congress and WSAA Symposium. Volume I Towards Enhanced and Sustainable Agricultural Production in the 2000's. Pages 189-200.

Keeling P.L., Banisadr R., Barone L., Wasserman B.P. and Singletary G.W. (1994). Effects of temperature on enzymes in the pathway of starch biosynthesis in developing wheat and maize grain. Aust J Pl Physiol. 21 807-827.

Mu, C., Harn, C., Ko, Y., Singletary, G. W., Keeling, P.L. and Wasserman, B.P. (1994) Association of a 76kDa polypeptide with soluble starch synthase I activity in maize (cv B73) endosperm.  Plant Journal 6,  151-159.

Keeling P.L., Bacon P.J. and Holt D.C. (1993) Elevated temperature reduces starch deposition in wheat endosperm by reducing the activity of soluble starch synthase. Planta, 191(3) 342-348.

Foxon G.A., Catt L. and Keeling P.L. (1990) Starch biosynthesis in developing wheat grain: The effect of light on endosperm starch synthesis in-vitro and in-vivo. Planta 181 104-108.

Keeling P.L., Baird S. and Tyson R.H. (1989) Isolation and properties of protoplasts from endosperm of developing wheat grain. Plant Science 65 55-62.

Keeling P.L., Wood J.R., Tyson R.H. and Bridges I.G. (1988) Starch biosynthesis in developing wheat grain: Evidence against the direct involvement of triose phosphates in the metabolic pathway. Plant Physiology  87 311-319.

Keeling P.L. and James P. (1986) Desalting and freeze-drying techniques to prepare plant derived neutral sugar extracts for quantitative HPLC. J. Liq. Chromatog. 9 983-992.

Keeling P.L., Smith L.L. and Aldridge W.N. (1982) The formation of mixed disulphides in rat lung following paraquat administration: correlation with changes in intermediary metabolism. Biochim. Biophys. Acta  716 249-257.

Keeling P.L. and Smith L.L. (1982) Relevance of NADPH depletion and formation of mixed disulphides in rat lung following paraquat poisoning to the mechanism of cell damage.  Biochem. Pharmacol.  31 3243-3249.

Keeling P.L., Pratt I.S., Aldridge W.N. and Smith L.L. (1981) The enhancement of paraquat toxicity in rats by 85% oxygen: lethality and cell specific lung damage.  Brit. J. Exp. Path. 62 642-654.

Pratt I.S., Keeling P.L. and Smith L.L. (1980) The effect of high concentrations of oxygen on paraquat and diquat toxicity in rats. Arch. Toxicol. Suppl.  4 415-418.

Pratt I.S., Keeling P.L. and Smith L.L. (1979) The effect of high concentrations of oxygen on the toxicity of paraquat and diquat in rats.  Toxicol. Appl. Pharmacol.  48 A59.