Introduction to Biochemistry
The introduction and history of biochemistry requires definition of Biochemistry firstly; biochemistry is the branch of science that is concerned or related to the chemical nature and chemical behaviour of living matter. In 1903, Carl Neuberg, a German Chemist for the very first time introduced the term “Biochemistry” (bios =life).
Biochemistry calculates and estimates by taking into account all the studies related to the nature of the chemical constituents of living matter, their transformations or conversions in biological systems and the energy changes or alterations associated with these transformations or conversions.
Such studies have been conducted in the tissues of both plants and animals. Broadly speaking, biochemistry may thus be treated as a discipline or interdisciplinary science in which biological phenomena are studied, examined and analyzed in terms of chemistry. Hence, for the very same reason, the branch of biochemistry has been variously named Biological Chemistry or Chemical Biology.
The history of biochemistry starts with the origin of Biochemistry was an offshoot from human physiology, and this fact of bifurcation came into knowledge when it was realized that the diagnosis of a particular disease can be assisted by the chemical analysis of urine, blood and other natural fluids. Hence in its inception, biochemistry was accordingly known as Chemical Physiology.
But now the study of Physiology covers the normal functions and phenomena occurring in the biological body of living beings. And in biochemistry, the study is particularly concerned with the chemical aspects or features of these functions and phenomena. In other words, specifically, biochemistry is but one of the many ways of studying physiology.
The two branches which are interconnected may be compared by watching the monkeys in a zoo which means studying the physiology of behavior or behavioral physiology. But if the study is conducted on the behavior of animal molecules rather than the whole animals, it would form the study of biochemistry.
The two branches of Modern biochemistry are descriptive biochemistry and dynamic biochemistry. Descriptive biochemistry is concerned or related with the qualitative and quantitative characterization of the various cell components and dynamic biochemistry is concerned with dealing with the illumination of the nature and the mechanism of the reactions which are involved in these cell components.
While the previous branch is more a concern of the organic chemist, the later branch has now become the language of modern biochemistry. Although the knowledge of biochemistry is boosting rapidly, new original disciplines/fields are emerging from the parent biochemistry.
Some of the fields and disciples which have been emerged and became prominent are enzymology (it is the science which deals with the study of enzymes), endocrinology (science which deals with the endocrine secretions or hormones), clinical biochemistry, molecular biochemistry etc.
Along with these disciplines, certain linked specialties have also popped such as agricultural biochemistry, pharmacological biochemistry etc. Now let us move towards the history of biochemistry.
History of Biochemistry
From a historical perspective, biochemistry is a recently emerged science. It took off mostly as a bifurcation of organic chemistry and later in the time it incorporated ideas and techniques obtained from physical chemistry.
It may be regarded that, the science and history of biochemistry has begun with the writings of Theophrastus Bombastus von Hohenheim, better known as Philippus Aureolus Paracelsus (lifetime or LT, 1493–1541), a Swedish physician and alchemist, he first learned and acquired the knowledge of chemistry of his time and then studied the field of medicine to apply his knowledge of chemistry.
Later, his followers notably Jan Baptist van Helmont (LT, 1577–1644) he Integrated or amalgamated the science of chemistry with the science of medicine which emerged under the name of ‘medical chemistry’ (or Iatrochemistry).
The basis of biochemistry was laid down by chemists like Scheele and Lavoisier.
Karl Wilhelm Scheele (LT, 1742–1786), a Swedish pharmacist, discovered the chemical composition of various drugs in the plant and he also isolated several substances such as citric acid from lime juice, uric acid from urine, malic acid from apple, and lactic acid from sour milk. Scheele, thus, the foundation of descriptive biochemistry was laid by Scheele.
Similarly, Antoine Lavoisier (LT, 1743–1794), a French chemist, studied the air composition and thoughtfully propounded the theory of conservation of matter, has placed the dynamic biochemistry on firm sand footings. He formulated and developed the concept of oxidation and also elucidated the nature of animal respiration. He deduced that respiration could be equated with combustion and that it was steeper but not essentially different from the combustion of charcoal. Lavoisier is often spoken of as the ‘father of modern biochemistry.
The preliminary book relating to Biochemistry was ‘Lectures in Animal Chemistry’ published by the famous Swedish chemist Jöns Jacob Berzelius (LT, 1779–1848).
A German chemist, in1828, named – Friedrich Wohler synthesized a substance of biological origin called “urea” in the laboratory from the inorganic compound ammonium cyanate. This successful discovery was the unexpected result of several attempts to prepare ammonium cyanates through the treatment of metal cyanates with ammonium salts.
Justus von Liebig, a German chemist and chloroform discoverer, who is often spoken of as ‘father of agricultural chemistry, concluded that “the nutritive materials of all green plants are inorganic substances”.
Hermann Emil Fisher (LT, 1852–1919) German biochemist, can be regarded as a landmark in the development of structural biochemistry. In the period of his studies and experiments, he came out as a remarkable man who completely revolutionized research associating with the structures of carbohydrates, amino acids and fats. However, nucleic acids are the most recent of the 4 great groups of biochemical materials.
Friedrich Miescher (LT, 1844–1895) in 1869, he discovered nucleic acids in the nuclei of pus cells, obtained from discarded surgical bandages, this led him to do the investigation and distribution of all the properties of these compounds.
Further studies and experiments on fermentations climaxed in 1887 by Eduard Buchner (LT, 1860–1917) he said that sugars could be fermented by cell-free extracts of yeast. This discovery tells about the cornerstone of much of the enzymological and metabolical study of the twentieth century.
Since it led to all the powerful techniques of isolation and characterization that permitted the study of enzymes and the individual reactions associated. Buchner’s work on cell-free fermentation of sugars was extended actively in many laboratories, such as in the lab of Harden and Young, Embden and Meyerhof, with the result the complete biochemical pathway known Embden-Meyerhof-Parnas pathway (or glycolysis) was illuminated.
The Experimental researches conducted by Warburg, Heinrich Wieland, Kellin and Theorell led them to the discovery of enzymes and several cofactors involved in cellular oxidation. Later, Fritz Albert Lipmann and Kurt Henseleit made observations on the importance of the terminal pyrophosphate linkages of ATP as an energy storage reservoir.
Two biochemists from England Albert Szent-Györgyi and Hans Adolf Krebs (LT, 1900–1981) analyzed the fate of lactate (or pyruvate) during aerobic oxidation. This work of analyzing lactate fate led to the development of a sequence of reactions known as the Krebs cycle (or citric acid cycle).
The complete amino acid sequence of insulin which is a protein hormone was established by Friedrick Sanger and the structure of the nonapeptide hormones of the posterior pituitary by direct synthesis was clarified and proved by du Vigneaud.
The brilliant experimental studies by Linus Carl Pauling and Robert Corey (LT, 18971971) led them to the concept of a secondary structure of protein molecules in the form of an α-helix. An indistinguishable kind of structure for the nucleic acids was also illuminated.
As the history of biochemistry progressed, James Dewey Watson and Francis Harry Compton Crick, in 1953, put forward that a double-stranded DNA molecule could be made by binding bases on adjacent strands to each other by hydrogen bonding.
Erwin Chargaff, an Austrian refugee biochemist established this base-pairing hypothesis by the quantitative data and after that in a very few time followed by the enzymatic synthesis of DNA by Arthur Kornberg. These synthetic macromolecules have properties that resemble the Watson-Crick hypothesis.
A complete final list of the base sequences in messenger RNA that code for each of the amino acids was produced as an outcome of the experimental researches by the scientist Marshall Nirenberg, who identified the coded base sequences for each of the amino acids by using synthetic nucleotides as messenger molecules.
James B Sumner (LT, 1887–1955) at Cornell University, for the first time, crystallized the enzyme “urease “ by extracting the samples from Jack bean and demonstrated and clarified its protein nature.
These discoveries have led to a hypothesis proposed in 1961 by two Frenchmen, Francois Jacob and Jacques Monod, they suggested that the DNA molecules consist of areas in which genes are supported and maintained in an inert phase or state by repressors until they are needed to be activated for the production of messenger RNA molecules.
Jacob and Monod, in 1963, with Jean-Pierre Changeux, also proposed a theory to emphasize the molecular aspects and features of regulation of the catalytic activity of enzymes.
In this era of biotechnology, biochemistry will continue to occupy a position of central importance. As a basic science, it is in the fore ranks of many scientific endeavors that stand to make a reality of the statement that “the twentieth century belongs to the biologists.”
Further Reading:
