History of biochemistry

Biochemistry began with the ancient Greeks who were interested in the composition and processes of life, although biochemistry as a specific scientific discipline has its beginning around the early 19th century. Some argue that the beginning of biochemistry may have been the discovery of the first enzyme, Diastase (today called amylase), in 1833 by Anselme Payen, while others considered the first demonstration, by Eduard Buchner, of a complex biochemical process: alcoholic fermentation in cell-free extracts. Some might also point to Justus von Liebig's influential work from 1842, Animal Chemistry or Organic Chemistry in its applications to physiology and pathology., which presented a chemical theory of metabolism, or even earlier to the 18th century studies of fermentation and respiration by Antoine Lavoisier.

The term "biochemistry" is derived from the combination bio-, which means "life", and chemistry. The word is first recorded in English in 1848, while in 1877, Felix Hoppe-Seyler used the term (Biochemie in German) in the foreword to the first edition of the Zeitschrift für Physiologische Chemie (Journal of Physiological Chemistry) as a synonym. for physiological chemistry and advocated the creation of institutes dedicated to his studies. However, several sources cite the German chemist Carl Neuberg as coining the term for the new discipline in 1903, while some credit Franz Hofmeister.

The subject of study of biochemistry is chemical processes in living organisms, and its history involves the discovery and understanding of the complex components of life and the elucidation of pathways of biochemical processes. Much of biochemistry deals with the structures and functions of cellular components such as proteins, carbohydrates, lipids, nucleic acids, and other biomolecules; its metabolic pathways and the flow of chemical energy through metabolism; how biological molecules give rise to the processes that occur within living cells; It also focuses on the biochemical processes involved in controlling the flow of information through biochemical signaling, and how they relate to the functioning of whole organisms.

Among the large number of different biomolecules, many are large, complex molecules (called polymers), which are composed of similar repeating subunits (called monomers). Each class of polymeric biomolecule has a different set of subunit types. For example, a protein is a polymer whose subunits are selected from a set of twenty or more amino acids, carbohydrates are formed from sugars known as monosaccharides, oligosaccharides, and polysaccharides, lipids are formed from fatty acids and glycerols, and fatty acids are formed. nucleic from nucleotides. Biochemistry studies the chemical properties of important biological molecules, such as proteins, and in particular the chemistry of enzyme-catalyzed reactions. The biochemistry of cell metabolism and the endocrine system has been widely described. Other areas of biochemistry include the genetic code (DNA, RNA), protein synthesis, cell membrane transport, and signal transduction.

Proto - biochemistry

In these respects, the study of biochemistry began when biology began to interest society - as the ancient Chinese developed a system of medicine based on yin and yang and also on the five phases,both resulting from alchemical and biological interests. It started in ancient Indian culture also with an interest in medicine as they developed the concept of three humors which were similar to the four Greek humors (see humorism). They also delved into the interest of bodies that are made up of tissues. As in most of the early sciences, the Islamic world contributed greatly to early biological as well as alchemical progress; especially with the introduction of clinical trials and clinical pharmacology presented in Avicenna's The Canon of Medicine.On the chemical side, early advances were heavily attributed to exploring alchemical interests but also included: metallurgy, the scientific method, and early theories of atomism. In more recent times, the study of chemistry was marked by milestones such as the development of Mendeleev's periodic table, Dalton's atomic model, and the conservation of mass theory. This last mention has the greatest importance of the three due to the fact that this law intertwines chemistry with thermodynamics in an interleaved manner.

Enzymes

As early as the late 18th and early 19th centuries, the digestion of meat by secretions from the stomach and the conversion of starch to sugars by plant extracts and saliva were known. However, the mechanism by which this occurred had not been identified. In the 19th century, studying the fermentation of sugar with alcohol by yeast, Louis Pasteur concluded that this fermentation was catalyzed by a vital force contained within the cells of yeast. yeast called ferments, which he thought functioned only within living organisms. He wrote that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells".

Anselme Payen discovered the first enzyme called diastase in 1833 and in 1878 the German physiologist Wilhelm Kühne (1837-1900) coined the term enzyme, which comes from the Greek ενζυμον "in yeast", to describe this process. The word enzyme was later used to refer to non-living substances such as pepsin, and the word ferment is used to refer to chemical activity produced by living organisms.

In 1897 Eduard Buchner began to study the ability of yeast extracts to ferment sugar despite the absence of living yeast cells. In a series of experiments at the University of Berlin, he found that sugar fermented even when there were no live yeast cells in the mixture. The name of the enzyme that caused the fermentation of sucrose was "zymase".In 1907 he received the Nobel Prize in Chemistry "for his biochemical research and his discovery of cell-free fermentation". Following the example of Buchner; Enzymes are usually named according to the reaction they carry out. Typically, the suffix -ase is added to the name of the substrate (for example, lactase is the enzyme that cleaves lactose) or the type of reaction (for example, DNA polymerase forms DNA polymers).

Having shown that enzymes could function outside of a living cell, the next step was to determine their biochemical nature. Many early researchers noted that enzyme activity was associated with proteins, but several scientists (such as Nobel laureate Richard Willstätter) argued that proteins were simply carriers of the true enzymes, and that the proteins themselves were incapable of catalysis. However, in 1926, James B. Sumner showed that the enzyme urease was a pure protein and crystallized it; Sumner did the same with the enzyme catalase in 1937. The conclusion that pure proteins can be enzymes was definitively proven by John Howard Northrop and Wendell Meredith Stanley, who worked on the digestive enzymes pepsin (1930), trypsin, and chymotrypsin.​

This discovery, that enzymes could be crystallized, meant that scientists could eventually resolve their structures using X-ray crystallography. This was first done for lysozyme, an enzyme found in tears, saliva, and egg whites. egg that digests the coating of some bacteria; the structure was solved by a group led by David Chilton Phillips and published in 1965. This high-resolution structure of lysozyme marked the beginning of the field of structural biology and the effort to understand how enzymes work at an atomic level of detail.

Metabolism

Initial metabolic interest

The term metabolism is derived from the Greek Μεταβολισμός - Metabolisms for "change", or "overthrow". The history of the scientific study of metabolism spans 800 years. The earliest of all metabolic studies began in the early 13th century (1213-1288) by a Muslim scholar from Damascus named Ibn al-Nafis. al-Nafis stated in his best-known work Theologus Autodidactus that "that body and all its parts are in a continual state of dissolution and nourishment, and are therefore inevitably undergoing permanent change." Although Al-Nafis was the first documented physician to be interested in biochemical concepts,This book describes how to weigh yourself before and after eating, sleeping, working, sex, fasting, drinking, and excreting. He found that most of the food he took in was lost with what he called "insensible perspiration".

Metabolism: 20th century - present

One of the most prolific of these modern biochemists was Hans Krebs who made enormous contributions to the study of metabolism. [26] Krebs was an extremely important student of Otto Warburg, and wrote a biography of Warburg by that title in which he presents Warburg as educated to do for biological chemistry what Fischer did for organic chemistry. What he did. Krebs discovered the urea cycle and later, working with Hans Kornberg, the citric acid cycle and the glyoxylate cycle. These findings led to Krebs being awarded the Nobel Prize in Physiology in 1953, which was shared with the German biochemist Fritz Albert Lipmann who also discovered the essential cofactor coenzyme A.

Glucose absorption

In 1960, biochemist Robert K. Crane revealed his discovery of sodium-glucose co-transport as a mechanism for intestinal glucose absorption. This was the first proposal for a coupling between ion and substrate fluxes to have been made. seen as the spark of a revolution in biology. This discovery, however, would not have been possible were it not for the discovery of the glucose molecule's structure and chemical composition. These discoveries are largely attributed to the German chemist Emil Fischer, who received the Nobel Prize in Chemistry almost 60 years earlier.

Glycolysis

Since metabolism focuses on the breakdown (catabolic processes) of molecules and the construction of larger molecules from these particles (anabolic processes), the use of glucose and its participation in the formation of adenosine triphosphate (ATP) is essential to this understanding. The most common type of glycolysis found in the body follows the Embden-Meyerhof-Parnas (EMP) pathway, which was discovered by Gustav Embden, Otto Fritz Meyerhof, and Jakob Karol Parnas. These three men discovered that glycolysis is a strongly determining process for the efficiency and production of the human body. The importance of the pathway shown in the adjacent image is that by identifying the individual steps in this process clinicians and researchers are able to identify sites of metabolic malfunction such as pyruvate kinase deficiency that can lead to severe anemia.. This is all the more important because cells, and therefore organisms, are not able to survive without well-functioning metabolic pathways.

Instrumental advances (20th century)

Since then, biochemistry has advanced, especially since the mid-20th century, with the development of new techniques such as chromatography, X-ray diffraction, NMR spectroscopy, radioisotopic labeling, electron microscopy, and molecular dynamics simulations. These techniques allowed the discovery and detailed analysis of many molecules and metabolic pathways in the cell, such as glycolysis and the Krebs cycle (citric acid cycle). The example of an NMR instrument shows that some of these instruments, such as HWB-NMR, can be very large in size and can cost from a few hundred dollars to millions of dollars ($16 million for the one shown here).).

Polymerase chain reaction

Polymerase chain reaction (PCR) is the main gene amplification technique that has revolutionized modern biochemistry. The polymerase chain reaction was developed by Kary Mullis in 1983.There are four steps to a proper polymerase chain reaction: 1) denaturation 2) extension 3) insertion (of the gene to be expressed) and finally 4) amplification of the inserted gene. These steps with simple illustrative examples of this process can be seen in the image below and to the right of this section. This technique allows a single gene copy to be amplified into hundreds or even millions of copies and has become a cornerstone of protocol for any biochemist wishing to work with bacteria and gene expression. PCR is not only used for gene expression research, but is also capable of helping laboratories diagnose certain diseases, such as lymphomas, some types of leukemia, and other malignancies that can sometimes confuse doctors.The development of the polymerase chain reaction theory and process is essential, but the invention of the thermocycler is equally important because the process would not be possible without this instrument. This is yet another testament to the fact that advancing technology is as crucial to sciences like biochemistry as is the painstaking research that leads to the development of theoretical concepts.