Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to living organisms. Biochemical processes give rise to the complexity of life.
In chemistry, a disulfide refers to a functional group with the structure R−S−S−R′. The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In biology, disulfide bridges formed between thiol groups in two cysteine residues are an important component of the secondary and tertiary structure of proteins. The connection is a persulfide, in analogy to its congener, peroxide (R−O−O−R′), but this terminology is rarely used, except in reference to hydrodisulfides.
A membrane transport protein is a membrane protein involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane. Transport proteins are integral transmembrane proteins; that is they exist permanently within and span the membrane across which they transport substances. The proteins may assist in the movement of substances by facilitated diffusion or active transport. The two main types of proteins involved in such transport are broadly categorized as either channels or carriers. The solute carriers and atypical SLCs are secondary active or facilitative transporters in humans.
Cystinuria is an inherited autosomal recessive disease that is characterized by high concentrations of the amino acid cysteine in the urine, leading to the formation of cystine stones in the kidneys, ureter, and bladder. It is a type of aminoaciduria.
A conotoxin is one of a group of neurotoxic peptides isolated from the venom of the marine cone snail, genus Conus.
The bicinchoninic acid assay, also known as the Smith assay, after its inventor, Paul K. Smith at the Pierce Chemical Company, is a biochemical assay for determining the total concentration of protein in a solution, similar to Lowry protein assay, Bradford protein assay or biuret reagent. The total protein concentration is exhibited by a color change of the sample solution from green to purple in proportion to protein concentration, which can then be measured using colorimetric techniques.
Cyanogen bromide is the inorganic compound with the formula (CN)Br or BrCN. It is a colorless solid that is widely used to modify biopolymers, fragment proteins and peptides, and synthesize other compounds. The compound is classified as a pseudohalogen.
N-Ethylmaleimide (NEM) is an organic compound that is derived from maleic acid. It contains the imide functional group, but more importantly it is an alkene that is reactive toward thiols and is commonly used to modify cysteine residues in proteins and peptides.
Sulfur is an essential element for growth and physiological functioning of plants. However, its content strongly varies between plant species and it ranges from 0.1 to 6% of the plants' dry weight.
TCEP is a reducing agent frequently used in biochemistry and molecular biology applications. It is often prepared and used as a hydrochloride salt (TCEP-HCl) with a molecular weight of 286.65 gram/mol. It is soluble in water and available as a stabilized solution at neutral pH and immobilized onto an agarose support to facilitate removal of the reducing agent.
Solute carrier family 7, member 9 also known as SLC7A9 is a protein which in humans is encoded by the SLC7A9 gene.
Cystine/glutamate transporter is an antiporter that in humans is encoded by the SLC7A11 gene.
Djenkolic acid is a sulfur-containing non-protein amino acid naturally found in djenkol beans of the South-East Asian legumes jengkol. Its chemical structure is similar to cystine but contains a methylene unit in between the two sulfur atoms.
Birtoxin is a neurotoxin from the venom of the South African Spitting scorpion. By changing sodium channel activation, the toxin promotes spontaneous and repetitive firing much like pyrethroid insecticides do
Huwentoxins (HWTX) are a group of neurotoxic peptides found in the venom of the Chinese bird spider Haplopelma schmidti. The species was formerly known as Haplopelma huwenum, Ornithoctonus huwena and Selenocosmia huwena. While structural similarity can be found among several of these toxins, HWTX as a group possess high functional diversity.
Sodium nitroprusside (SNP), sold under the brand name Nitropress among others, is a medication used to lower blood pressure. This may be done if the blood pressure is very high and resulting in symptoms, in certain types of heart failure, and during surgery to decrease bleeding. It is used by continuous injection into a vein. Onset is typically immediate and effects last for up to ten minutes.
The Sakaguchi test is a chemical test used for detecting the presence of arginine in proteins. It is named after the Japanese Food Scientist and Organic Chemist, Shoyo Sakaguchi (1900–1995) who described the test in 1925. Sakaguchi reagent consists of 1-Naphthol and a drop of sodium hypobromite. The guanidine group in arginine reacts with Sakaguchi reagent to form a red-coloured complex.
The Hopkins-Cole reaction, also known as the glyoxylic acid reaction, is a chemical test used for detecting the presence of tryptophan in proteins. A protein solution is mixed with Hopkins Cole reagent, which consists of glyoxylic acid. Concentrated sulfuric acid is slowly added to form two layers. A purple ring appears between the two layers if the test is positive for tryptophan. Nitrites, chlorates, nitrates and excess chlorides prevent the reaction from occurring.
