The history of biochemistry began with the ancient Greeks, who studied the makeup and processes of life. However, biochemistry as a scientific field started around the early 1800s. Some people believe the start of biochemistry was when Anselme Payen discovered the first enzyme, diastase (now called amylase), in 1833. Others think Eduard Buchner’s 1897 experiment showing alcoholic fermentation in cell-free extracts marked the beginning. Some also mention Justus von Liebig’s 1842 work, Animal Chemistry, which explained metabolism through chemistry, or Antoine Lavoisier’s 18th-century studies on fermentation and respiration as important early steps.

The word "biochemistry" combines "bio-" (meaning life) and "chemistry." It was first used in English in 1848. In 1877, Felix Hoppe-Seyler used the term Biochemie in German to describe physiological chemistry and suggested creating institutes to study it. However, some sources credit Carl Neuberg with coining the term in 1903, while others mention Franz Hofmeister.

Biochemistry studies the chemical processes in living things. Its history includes discovering and understanding life’s complex parts and how biochemical processes work. Biochemistry focuses on structures and functions of molecules like proteins, carbohydrates, lipids, and nucleic acids, as well as their roles in metabolism and energy transfer. It also examines how molecules control information flow through signaling and how these processes affect entire organisms. Over the past 40 years, biochemistry has helped explain many life processes, making it a key part of fields like medicine and botany.

Many biomolecules are large, complex structures called polymers made of repeating units called monomers. For example, proteins are polymers made of amino acids; carbohydrates include sugars like monosaccharides and polysaccharides; lipids are made of fatty acids and glycerol; and nucleic acids are made of nucleotides. Biochemistry studies the chemical properties of these molecules, especially enzyme reactions. It also explores topics like cell metabolism, the endocrine system, the genetic code (DNA and RNA), protein synthesis, cell membrane transport, and signal transduction.

Proto-biochemistry

The study of biochemistry began a long time ago, even before modern science existed. For example, ancient Chinese people created a medical system based on ideas like yin and yang and the five phases, which came from early chemical and biological studies. In ancient India, people developed a medical idea about three bodily fluids, similar to the Greek idea of four humors. They also studied how the body is made of tissues. The ancient Greeks believed that health depended on balancing the four elements and four humors in the body. Early scientists in the Islamic world made important contributions to biology and chemistry, such as introducing clinical trials and medicine studies in Avicenna’s The Canon of Medicine. In chemistry, early progress included exploring alchemy, metallurgy, and the scientific method, as well as early ideas about atoms. More recently, chemistry advanced with discoveries like Mendeleev’s periodic table, Dalton’s atomic model, and the law of conservation of mass. This last discovery is especially important because it connects chemistry with thermodynamics in a special way.

Enzymes

As early as the late 1700s and early 1800s, people knew that stomach juices helped break down meat and that plants and saliva changed starch into sugar. However, they did not understand how these changes happened.

In the 1800s, Louis Pasteur studied how yeast turned sugar into alcohol. He believed this process was caused by a special force inside yeast cells called "ferments," which he thought only worked in living things. He wrote that "alcoholic fermentation is connected to the life of yeast cells, not their death or decay."

In 1833, Anselme Payen discovered the first enzyme, called diastase. In 1878, Wilhelm Kühne created the word "enzyme," which comes from the Greek word for "in leaven" (a type of bread-making ingredient). Later, the word "enzyme" was used for nonliving substances like pepsin, while "ferment" described chemical reactions made by living organisms.

In 1897, Eduard Buchner studied whether yeast extracts could turn sugar into alcohol without living yeast cells. At the University of Berlin, he found that sugar was still fermented even without yeast. He named the enzyme that caused this process "zymase." In 1907, Buchner won the Nobel Prize in Chemistry for his discovery of "cell-free fermentation." Today, enzymes are often named based on the reaction they perform, with the suffix "-ase" added (for example, lactase breaks down lactose).

After showing that enzymes could work outside living cells, scientists tried to learn more about their chemical nature. Early studies showed that enzymes were linked to proteins, but some scientists, like Richard Willstätter, thought proteins were only carriers for real enzymes. However, in 1926, James B. Sumner proved that the enzyme urease was a pure protein and made it into crystals. He did the same for catalase in 1937. Later, Northrop and Stanley showed that proteins like pepsin, trypsin, and chymotrypsin were enzymes. These scientists won the 1946 Nobel Prize in Chemistry.

The ability to crystallize enzymes allowed scientists to study their structures using a method called x-ray crystallography. This was first done for lysozyme, an enzyme found in tears, saliva, and egg whites that breaks down bacteria. A team led by David Chilton Phillips discovered lysozyme’s structure in 1965. This discovery started the field of structural biology, helping scientists understand how enzymes work at the atomic level.

Metabolism

The word "metabolism" comes from the Greek word "metabolismos," which means "change" or "overthrow." Scientists have studied metabolism for about 800 years. The earliest known research on metabolism began in the early 13th century (1213–1288) by a Muslim scholar named Ibn al-Nafis from Damascus. In his book Theologus Autodidactus, he wrote that the body and all its parts are constantly changing through processes of breaking down and rebuilding. Although Ibn al-Nafis was the first recorded doctor to study biochemical ideas, the first controlled experiments on human metabolism were published in 1614 by Santorio Santorio in his book Ars de statica medecina. In this book, he described how he weighed himself before and after eating, sleeping, working, having sex, fasting, drinking, and excreting. He discovered that most of the food he consumed was lost through a process he called "insensible perspiration."

One of the most active modern biochemists was Hans Krebs, who made major contributions to the study of metabolism. Krebs studied under Otto Warburg, an important scientist, and later wrote a biography about Warburg, describing how Warburg helped develop biological chemistry in the same way Emil Fischer helped develop organic chemistry. Krebs discovered the urea cycle and later, with Hans Kornberg, the citric acid cycle and the glyoxylate cycle. These discoveries earned Krebs the Nobel Prize in physiology in 1953, which he shared with the German biochemist Fritz Albert Lipmann, who also discovered the essential cofactor coenzyme A.

In 1960, the biochemist Robert K. Crane discovered the sodium-glucose cotransport mechanism, which explains how the intestines absorb glucose. This was the first time scientists proposed that the movement of an ion and a substance could be connected, an idea that sparked major changes in biology. However, this discovery would not have been possible without earlier work on the structure and chemical makeup of glucose. These discoveries are largely credited to the German chemist Emil Fischer, who received the Nobel Prize in chemistry nearly 60 years earlier.

Metabolism involves breaking down molecules (catabolic processes) and building larger molecules from smaller ones (anabolic processes). The use of glucose and its role in creating adenosine triphosphate (ATP) is essential to understanding these processes. The most common type of glycolysis in the body follows the Embden-Meyerhof-Parnas (EMP) Pathway, discovered by Gustav Embden, Otto Meyerhof, and Jakob Karol Parnas. These scientists found that glycolysis is a key process for the body's efficiency and energy production. The pathway shown in the image next to this text is important because it helps doctors and researchers identify problems in metabolic processes, such as pyruvate kinase deficiency, which can cause serious anemia. This is crucial because cells—and the organisms they support—cannot survive without properly functioning metabolic pathways.

Instrumental advancements (20th century)

Since the mid-20th century, biochemistry has made many advances. Scientists developed new tools, such as chromatography, X-ray diffraction, NMR spectroscopy, radioisotopic labeling, electron microscopy, and molecular dynamics simulations. These tools helped scientists discover and study many molecules and processes inside cells, such as glycolysis and the Krebs cycle. Some instruments, like the HWB-NMR, can be very large and cost from a few thousand dollars to millions of dollars. For example, the one shown here costs $16 million.

Polymerase chain reaction (PCR) is a key technique used to copy genes. It was developed by Kary Mullis in 1983. A proper PCR process has four steps: 1) denaturation, 2) extension, 3) insertion (adding the gene to be studied), and 4) amplification (making many copies of the gene). These steps are shown in an image nearby. PCR allows scientists to copy a single gene into hundreds or even millions of copies. This technique is essential for biochemists who study bacteria and gene activity. PCR is also used to help diagnose diseases such as lymphomas and some types of leukemia. Without PCR, many discoveries in bacterial and protein research would not have happened. The development of PCR theory is important, but the invention of the thermal cycler is equally vital because the process cannot happen without this machine. This shows that technological tools are as important as scientific research in advancing fields like biochemistry.