Sir Hopkins best remembered for his discovery of ‘vitamins’ has contributed immensely to the field of biochemistry, which was initiated as physiological chemistry on the continent. It is difficult to discuss in detail all the significant discoveries made by him in this article. Some of the most important discoveries, which shaped the field of biochemistry, are highlighted by Hiteshi Dhami-Shah, a Clinical Nutritionist and Research Fellow at Kasturba Health Society – Medical Research Centre, Mumbai, in this article.
|Sir Fredrick Gowland Hopkins|
The discovery and establishment of dynamic biochemistry as a subject can be credited to Sir Frederick Gowland Hopkins. Popularly known as the ‘father of biochemistry’, Hopkins is best remembered for his discovery of ‘vitamins’, with Christiaan Eijkman, for which they were jointly, awarded the Nobel Prize for Physiology or Medicine in 1929. In addition to the Nobel Prize, Hopkins was conferred with numerous awards like the Royal Medal and the Copley Medal of the Royal Society, Fellowship of the Royal Society, knighthood by King George V and the award of the Order of Merit. Inspite of having such an illustrious career, his life has enough struggles. Probably, the early hardship in life prepared him to earn laurels in later life, with grace and dignity.
Frederick Gowland Hopkins was born in Eastbourne, England on June 20, 1861. Ever since early childhood his inclination towards science was evident. This can be observed from his childhood tryst with his father’s microscope. He later wrote for the microscope that; ‘It was the most important thing I had yet come up against; so much more significant than anything I was being taught at school’. The kind of education he received in school never appealed and excited his intelligence. He left schools after changing a couple of them at the age of 17. So now he had to go in an insurance company. But he was salvaged within six months. Despite the advice by Sir Frederick Abel (a cousin of his father and a scientist, famous for his work on tides and currents) to send him to Cambridge, he was made a pupil in a private analytical laboratory.
As a boy he had shown interest in butterflies and beetles and published his first paper in Entomologist on the habits of Brachinus crepitans (Hopkins, 1878). But the field of physiology and chemistry had not gripped his imagination yet to become his lifelong passion. At the age of 20 Hopkins choose to dedicate to analytical chemistry. He later decided to work for the Fellowship of the Institute of Chemistry, and for this reason attended classes at University College, London. He passed the examination with flying colours and was invited by Sir Thomas Stevenson, the Home Office analyst and medical jurist to work as his assistant in his laboratory located in Guy’s Hospital. The forensic experience equipped him with a keen detective like sense to pursue cause of diseases.
During his second year with Sir Stevenson, he worked for the London External Degree and matriculated in 1887 at the age of 26, by studying in the evenings and during his train journeys. While he was working with Sir Stevenson, he came in contact with medicine and medical students. They would often discuss problems of physiological chemistry and it was one of these students (Sir Charles Martin) who wanted Hopkins to abandon analytical chemistry and begin research in physiological chemistry. His passion to pursue research in physiological chemistry grew stronger day-by-day. The entry into this field was through medicine and at the age of 27 in the year 1888, Hopkins enrolled at Guy’s hospital as a medical student. He passed intermediate BSc in 1888 and BSc in 1890 (honours in chemistry and physiology and gold medal in chemistry) and later M.R.C.S, L.C.P.S and M.B. (London) in 1894.
During this time, at the age of 37 he also got married to Jessie Stevens (1898) – later Lady Hopkins, a professional nurse who played a vital role in supporting her husband’s research career which was not financially rewarding. At a meeting of the physiological society held in 1898, Sir Michael Foster invited Hopkins to his physiological laboratory at Cambridge to develop teaching and research in physiological chemistry. In those days biochemistry was not identified as a separate discipline. His passion for research tempted him to take up the position at Cambridge which paid him only £200 per annum. With the support of Lady Hopkins, they moved to Cambridge the same year. Thus began the making of a pioneer biochemist. During his prolific research career he made various path-breaking discoveries, which created a better understanding of nutritional biochemistry and insights into the role of vitamins and amino acids.
The initial years at Cambridge were arduous. Sir Foster, whom Hopkins admired and who was also responsible for moving him to Cambridge, died in 1907. This prolonged his initial adverse circumstances but things gradually started falling in place. Cambridge offered him readership in biochemistry. His meager university stipend was supported by Emmanuel College, which appointed him to supervise their medical students in anatomy and physiology. Thus continuous touch with the foundational subjects of medicines was instrumental in keeping the chemist in Hopkins grounded in human organism and biochemistry. Finally in 1905 he was awarded F.R.S. His election as a Fellow at Trinity College (1910) ended his work at Emmanuel. In 1914 he was appointed the first Professor of Biochemistry in Cambridge and for the first time had a professional income and a department. Hopkins was much sought after for his lectures on biochemistry as a fundamental science of life. When the Sir William Dunn Institute opened in 1921 he was given the new Chair founded with it, which he held until retirement (1943). Though his journey in science started at the age of 17, he was recognised for his scientific work at 68.
When Sir Hopkins joined the physiological laboratory in Cambridge, his first paper was regarding description of crystallization of egg albumin. In 1901, Hopkin’s biological interest led him to discover the essential amino acid, tryptophan and investigate its importance in mammalian diet for growth. He showed in his experiments that when mice are fed zein, a maize protein that does not contain tryptophan, the animals stopped growing normally and died soon. This implicated that tryptophan is essential for growth and survival significantly.
Later, Hopkins’ study in 1907 with Sir Walter Morley Fletcher on the connection between lactic acid and muscle contraction is considered one of the most important studies on biochemistry of the cell even today. He and Fletcher showed that oxygen depletion causes an accumulation of lactic acid in the muscle. Fifteen years later, Hopkins isolated from living tissue the tripeptide (three amino acids linked in sequence) glutathione and showed that it is vital to the utilization of oxygen by the cell. Their work paved the way for the later discovery by Archibald Hill and Otto Fritz Meyerhof that a carbohydrate metabolic cycle supplies the energy used for the muscle contraction.
In 1912, Hopkins published the work for which he is best known. In a series of animal feeding experiments he showed that diets consisting of pure proteins, carbohydrates, fats, minerals, and water fail to support animal growth. He suggested that tiny quantities of unidentified substances which he called ‘accessory food factors’ at that time are essential for animal growth and survival. These substances were later named as ‘vitamins’, which is a household term today. It was this work that led to awarding him a Nobel Prize (1929) in Physiology or Medicine with Christiaan Eijkman.
During World War I Hopkins’ research and guidance were extremely important in time of food shortages and rationing. He discovered that margarine was inferior to butter because it lacked Vitamins A and D. As a result, vitamin-enriched margarine was introduced in 1926. Hopkins also rescued several scientists from Nazi Germany during the inter-war period. The most notable scientist among them was Hans Krebs, who discovered the citric acid cycle at Cambridge in 1933.
In 1923, Hopkins in association with Morgan and Stewart published an important paper on purine metabolism and oxidation of xanthine and hypoxanthine to uric acid by the enzyme xanthine oxidase found in milk and animal tissues. Between 1931 and 1936, Hopkins was pre-occupied with his duties as President of the Royal Society. In 1937 when he returned to the laboratory he focussed on the problems related to the function of thiol groups in enzymes and the role they play in maintaining active substances in the cell in reduced condition.
Besides his passion in research, Hopkins was also a staunch supporter of women’s education and research. He employed many women scientists in his laboratories despite the criticism he faced. This was a highly unusual practice at the time as there were virtually no women researchers in any Cambridge department. Amongst his most famous women scientists are Marjory Stephenson, Dorothy Needham and Muriel Wheldale. As time progressed, his health took a setback. In 1939, he underwent an operation after which his health woefully declined. He started losing eye sight and largely carried out his laboratory work with the help of his assistant, James Morgan. His last seven papers were during these difficult circumstances. Sir Frederick Hopkins passed away on May 16, 1947.
Without doubt Hopkins inspired his contemporaries and future generations to take up research in the field of biochemistry and develop the subject as we know it today. He is rightly called the ‘father of biochemistry’. It is important to note that at the time of his death only one university in England and one in Scotland had established biochemistry as a subject for a degree or had attempted to share with Cambridge the task of training biochemists for the future.
In his own words ‘the future scientific medical studies should always be carried out by men who, though medically qualified, have preferred the laboratory to practice, yet in middle region these must be joined in their work by men whose primary qualifications are non-medical, men who saved from the long years of clinical study are able to bring well grounded laboratory knowledge to join their medically qualified confreres in attacking the huge problems which await solution’.
About the author
Hiteshi Dhami-Shah is a Consultant Clinical Nutritionist in the area of Cardio-Metabolic Disorders and Child Health. She is a regular nutrition writer and has more than 80 articles published in popular health magazines and newspapers like Times Wellness, JADE, Complete Wellbeing, Men's Health, Stay Fit and Mid-day. She is also an Assistant Editor for Journal of Obesity and Metabolic Research.