Biochemistry Definition

what is biochemistry?

The biochemistry, formerly called physiological chemistry, is the study of chemical processes in living organisms, metabolism. Chemistry, biology and medicine are closely linked with each other in biochemistry. The Enlightenment and healing of metabolic diseases, such. As hormone deficiency (eg., Diabetes), vitamin deficiency were made possible by the biochemistry. Doctors can find some causes of disease faster by enzyme assays.


Biochemistry deals with:

-The study of biomolecular structures: how are the biomolecules constructed as is the molecular structure of the organism of living beings, as are the molecular building blocks provided and how they interact with each other?
-The study of metabolism: which substances are reacted as living beings, which bioenergetic conditions are necessary, which biocatalysts are involved, such as extending the respective mechanisms of biogeochemical cycles and how the metabolism is controlled?
-The study of information exchange within an organism and between organisms: how information is stored, retrieved and forwarded to various systems within a cell, between cells and between organisms coordinates?

In the course of the observations focus on the substance groups of the nucleic acids, proteins, lipids and carbohydrates and their derivatives, which are generally referred to as biomolecules. The majority of biochemically important processes take place in living organisms and thus in an aqueous medium.


In biochemistry, a variety of methods from different areas is used. The classical biochemistry operated primarily in analytical chemistry, organic chemistry, physical chemistry and physics. Important techniques are (ultra) centrifugation, ultrasonic digestion, SDS-gel electrophoresis, chromatography, electrophoresis, spectroscopy, radioactive labeling (tracer (nuclear medicine)), isotope techniques, crystallization, potentiometric, electrochemical metric, polarographic and manometric techniques, cell wall start by cooling, the Ames test came in the last decades to and molecular biological methods and methods from computer science, microbiology and other subjects. Moreover in modern biochemistry always the quantitative evaluation of the results with mathematical methods and the formation of formal theories with the help of mathematics.


Since the beginning of the 19th century, the first substances from the animal and plant kingdoms were systematically studied by organic chemists. It could be determined from biological material by elemental analysis of carbon, hydrogen, nitrogen and sulfur. From 1860, chemical structural formulas of substances in elemental composition could be determined by mental combination, now began a thorough search of the biological bodies in organisms. The search was due to the very small quantity of biomolecules and the lack of detection methods - even the elemental analysis required greater quantities of material - very time consuming and not always successful. Only with improvement of analytical instruments from 1950, the search and structure determination of biomolecules was easier.

Proteins and fats
Fats were examined by Eugene Chevreul and later by Heinrich Wilhelm Heintz. Gerardus Johannes Mulder could from the fibrin of the blood produce a gelantinösen precipitation and gave him the name of protein. Louis Nicolas Vauquelin examined the composition of the hair and found the chemical elements carbon, hydrogen, nitrogen, oxygen and sulfur.

Amino acid
Pierre Jean Robiquet and Louis Nicolas Vauquelin were also the first amino acid which isolated in 1805: Asparagine. Joseph Louis Proust discovered Leucine (1818), Justus von Liebig tyrosine (1846). Between 1865 and 1901 more 12 amino acids were discovered, of which Ernst Schulze discovered three new amino acids: phenylalanine, glutamine and arginine. First peptide syntheses were undertaken by Emil Fischer in 1901.

Justus Liebig realized that in yeast a special fabric had to be included, which triggers the fermentation. He called this substance BIOS. The term biochemistry was used for the first time as Vinzenz Kletzinsky (1826-1882) his "Compendium of Biochemistry" in Vienna had in 1858. Felix Hoppe-Seyler (lactic acid from glycogen, oxidation-reduction enzymes, hemoglobin), Georg Carl Ludwig Sigwart (analysis of urinary stones and bile - excreting), Anselme Payen (1833: amylase), Julius Eugen Castle Hall (creatine, Hemocyanin) advanced the biochemical knowledge.

Was discovered amylase (then diastase) in 1833 by the French chemist Anselme Payen in a Malzlösung. This diastase was the first enzyme that has been found.

Early 19th century was also known that during fermentation of dead organisms of oxygen from the air is necessary, also temperature and water had an influence on this process. When dead animals and people putrefaction sets a first in the places that come in contact with the air. Even with botanicals, the formation of alcohol from grape juice solution or the acidification of milk recognized chemist fermentation processes. The body, which favored this process was called Ferment. Eduard Buchner discovered in 1896, the cell-free fermentation. James B. Sumner 1926 isolated the enzyme of the sword bean, claiming that all enzymes should be proteins.

John Howard Northrop isolated a few years later, pepsin, trypsin and chymotrypsin in crystalline form and was able to confirm hypothesis Sumners.

Nucleic acid
The physiologist Friedrich Miescher had discovered the 1870 nucleoproteids in the nucleus. Albrecht Kossel discovered the nucleic acid adenine (1885). He received further nucleic acids from animal extract, namely guanine, xanthine (1893), thymine (1894), cytosine and uracil (1903). Emil Fischer get the first syntheses of adenine, theophylline, thymine and uracil (1897-1903). Phoebus Levene examined the linkage of a nucleic acid with a pentose phosphate and a mono-nucleotide to (1908).

Carbohydrates are an important part of our diet, they were therefore temporarily investigated by biochemists. Both starch and sugars are broken down into glucose and stored in an oversupply in the liver as glycogen. A constant blood sugar is vital for the brain and the muscles. Adolf von Baeyer was in 1870 to a first formula for glucose. Emil Fischer made from 1887 extensive research to elucidate the chemical structures of sugars with phenylhydrazine to well crystallizable osazones. In 1893 he was able to convert glucose with methanol to methyl glycoside - prove that the aldehyde group linked in the ring with a hydroxyl group (glycoside) is - not reduced Fehling's solution. Later (1922) concluded Burckhardt Helferich that the glucose had (1,5-glycosidically instead of 1,4-glycoside) are present in a six-membered ring. Other important work on sugar chemistry and their structural representation made Norman Haworth; He also synthesized for the first time vitamin C (scurvy occurs when lack of), an acid derivative of a sugar.

By poor diet, many people died at the beginning of the 20th century. In 1882 Gustav studied rats and mice, he fed only with protein, carbohydrate and fat, their food but no other additives contained by Bunge. The animals died. People need more vitamins in addition to proteins, carbohydrates, fats. Many vitamins have been found at the beginning of the 20th century. The structure elucidation of cholesterol (and thus the Group of steroids) by Adolf wind was significant for the structure and formation of vitamin D (whose deficiency rickets occurs). Wind was also involved in the reconnaissance of the formula and structure of vitamin B1. Sir Frederick Gowland Hopkins, a pioneer of Biochemistry in the UK and Casimir Funk, vitamin coined the word, contributed significant research to the discovery of vitamin B1 (beri-beri occurs when deficiency). Hopkins discovered two essential amino acids and for 1929 was awarded the Nobel Prize. In 1926, Otto Warburg discovered the respiratory enzyme oxidase, an enzyme in the citric acid cycle and for Redoxvorgänge of the cell, for which he received the Nobel Prize in 1931.

After Ernest Starling hormones called groups of substances which are produced in human organs. In 1849, Thomas Addison discovered a disease that has its origins in the adrenal glands. A substance they called adrenaline from animal kidneys are extracted by T. B. Aldrich and Dr. Takamine Jokichi (1901). Aldrich determined the empirical formula and Friedrich Stolz was the chemical synthesis (1904). Thus, the artificial production of a hormone in 1904 first was biochemistry.

The goiter is a further hormonal disease of the thyroid gland, which could be mitigated by iodine gifts since 1820 after Jean-François Coindet. Until 1915, the isolation of a crystalline substance of thyroid succeeded Edward Calvin Kendall. He mistook her for an Oxindolderivat and named it therefore thyroxine. Synthetic thyroxine has been displayed since 1926 by Charles Robert Harington.

In 1935 Ernst Laqueur isolated from bull testicles as the designee sex hormone testosterone. Also by Adolf Butenandt sex hormones were studied. In 1929 he isolated estrone with one of the female sex hormones. Two years later, he isolated with androsterone, a male sex hormone. In 1934 he discovered the hormone progesterone. Was shown through his research that the sex hormones are closely related to steroids. Its investigations in the field of sex hormones allowed the synthesis of cortisol and other steroids. This eventually led to the development of modern contraceptives.

The lack of the pancreatic hormone could be alleviated by administration of bovine insulin in 1920 by Frederick Banting and Best. Not until 1953 did the amino acid sequence of insulin was elucidated by Frederick Sanger.

Important research areas of modern biochemistry

In textbooks of biochemistry, the processes of fermentation of sugar to ethanol and lactic acid, and the development of glucose to glycogen are described in detail. These conversions are grouped under the heading of glycolysis.

The energy in living cells via the breakdown of fats, amino acids and carbohydrates on oxaloacetate into citrate by acetyl-S-CoA, releasing carbon dioxide and energy. Acetyl S-CoA comprising a water-soluble vitamin - pantothenic acid. This process has been studied by H. Krebs citric acid cycle in 1937 and is called.

Oxidation of biomolecules in cells extend over several enzymes in which the vitamin B2 is involved. This process is described in textbooks as oxidative phosphorylation or respiratory chain.

Another very important biochemical process is photosynthesis. Carbon dioxide from the air and water is transferred by means of radiation energy by the pigment chlorophyll in plant cells into carbohydrates and oxygen.

In human and animal organisms, excess energy from food in the form of fats is stored. When power levels of the cells, these fats are broken down again. This process occurs via the oxidation of fatty acids via acetyl CoA.

In diseases (severe diabetes) or extreme food shortages cells rely on amino acids for energy. Here, proteins to amino acids and these are broken down to carbon dioxide. The urea cycle describes the transformations occurring.

In plant and animal cells carbohydrates can from other substances - be biochemically established - for example, the lactic acid or of amino acids. The studies of the individual biochemical steps are examined in gluconeogenesis. Furthermore, the biosynthesis of amino acids, nucleotides, porphyrins, the nitrogen cycle were examined thoroughly in plants.

Another portion of the biochemical research is the absorption and transport of metabolites through the blood plasma.

The transfer of the stored information in the cell nucleus in the DNA (or more precisely of certain portions of the DNA, genes) for the production of enzymes proceeds by replication, transcription and protein synthesis. This is a very important field of synthetic Biochemistry (biotechnology), since bacteria can be induced to their cyclic DNA (plasmids) to produce certain enzymes.

Individual proteins can be detected by gel electrophoresis. By Edman degradation of the amino acid sequence of the protein can be determined.

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