Professor Geoffrey Gilbert

Biophysical chemist who worked on proteins

Geoffrey Gilbert was one of the physical chemists of the second half of the 20th century who resolved many paradoxes produced by experimental work on proteins in solution.

Geoffrey Alan Gilbert, biophysical scientist: born Watford, Middlesex 3 December 1917; Lecturer, Department of Chemistry, Birmingham University 1943-46, Senior Lecturer 1947-61, Reader 1961-69, Professor of Biochemistry 1969-85 (Emeritus); FRS 1973; married 1948 Lilo Czigler de Egerszalok (two sons); died Birmingham 1 March 2005.

Geoffrey Gilbert was one of the physical chemists of the second half of the 20th century who resolved many paradoxes produced by experimental work on proteins in solution.

Born in Watford, Middlesex, in 1917, he was one of the brilliant young pupils of the 1930s who won scholarships to Cambridge University. He studied Chemistry at Emmanuel College and following his BSc remained to do research work in the Colloid Laboratory under the supervision of Sir Eric Rideal. His basic work was on the physical chemistry of dying wool where he applied his detailed knowledge of statistical thermodynamics to formulate a model known as the Gilbert-Rideal model for staining proteins.

Following his award of a PhD, in 1943 he was appointed Lecturer in Chemistry at Birmingham University, working under Sir Norman Howarth. At this time, the major research of this department was carbohydrate chemistry. Gilbert made great contributions to the physical chemistry of macro molecules, especially starch and its properties as a natural polymer. During this work, he discovered how free radicals which are present in alkaline aqueous solutions degraded the carbohydrate chains.

Following a year at Harvard Medical School (1946-47) he returned to Birmingham as Senior Lecturer (where he remained until his retirement as Professor of Biochemistry in 1985). In 1948 he married Lilo Czigler de Egerszalok, then a postgraduate student from Hungary. She became his constant companion, working in the laboratory while raising their two sons.

It was during this time that serendipity controlled his future. Gilbert noted some results from electrophoresis experiments on proteins presented at a Faraday Society meeting. The apparent paradox stimulated him to remember his elementary physical chemistry. He realised that these results came from a molecule that was reversibly dissociating into individual peptide chains. For the rest of his research career he studied reversibly dissociating proteins and notably haemoglobin protein in blood.

This work started in the late 1950s at a time when biophysics was blossoming. Max Perutz and John Kendrew using X-ray crystallography had given us the first three-dimensional structures of proteins (haemoglobin and myoglobin) while Francis Crick and James Watson had described the double helix of DNA. There were many unexplained physiological properties of the proteins but these new structures suddenly gave access to their understanding. It was in this environment that Geoffrey Gilbert began his major work.

The experiments he used employed equipment like electrophoresis (separation by electric charges), light scattering and ultracentrifuge (both measuring the mass of large molecules). The results, either in the form of complex optical patterns or derived curves, are easy to understand for homogeneous solutions, but, in the case of dissociating molecules, the solutions act as though they were mixtures of correlated molecules, making interpretation difficult. Gilbert began deriving the necessary mathematical models to describe the results.

The models were complex differential equations, usually with no direct analytical solution. He realised then that, by reducing the experimental variables within his model, he could compare the theoretical diagrams directly with experimental results. From these comparisons, he was able to explain in simple physical chemical terms several paradoxes in the results for many proteins. The work also complemented the biochemical studies of various enzymes known as allosteric effects involving the realignment of peptide chains within a molecule occurring during the enzyme reaction.

Later, in 1969, Gilbert realised that similar studies could be made using relatively simple methods in general use in biochemical laboratories. He preferred spending his time on experimental work and developing his theory - which became known as the Gilbert theory - to writing about it. His work concerned the energies binding different peptides (called subunits) together in the active protein. His analytical work excited many biophysicists in the United States and Europe and he was invited to numerous meetings dealing with protein properties. He worked for some periods, with his wife Lilo, in laboratories abroad.

Gilbert managed to include, with his teaching and research, administrative chores associated with science. He was a member of two scientific editorial boards, the Government Grants Committee (Biological Sciences) and British National Committee for Biochemistry, and was chairman of the British Biophysical Society in 1974. He was elected Fellow of the Royal Society in 1973.

In all this, Lilo was central to his scientific work. She carried out the computing required to convert his differential equations into usable pictures and patterns. They were the ideal scientific couple.

Following retirement in 1985, Geoffrey Gilbert took up many pursuits, including photography and, most importantly, the scientific study of composting. This came naturally from his keen interest in gardening, and his uncanny empathy with birds and urban wild animals like foxes.

Peter Spragg