The term copurification—especially in the study of chemistry and biochemistry—refers to the process of physical separation, using either chromatography or one of the many purification techniques. This process involves two or more substances of interest, which will then be separated from other substances that are considered to be contaminants. The substances involved in the process of copurification typically attract each other in order to form a noncovalent complex (for example, a protein complex).
In some cases, however, the fractionating of mixtures—especially when these mixtures have a large number of components (such as in the case of a cell lysate), chances are that some of the components might copurify even though they do not form noncovalent complexes. In the context of these cases, the term copurification can be used to refer to the process in which two biochemical activities or some other properties are isolated together after a purification procedure. But it is important to note that it is not always certain if a specific sample has been purified to homogeneity, which means that it contains only one molecular species or a single molecular complex. These activities or properties are like within the process of copurification, but the process cannot guarantee to reside on the same molecule or even in the same molecular complex.
Copurification procedures, including co-immunoprecipitation, are typically utilized to analyze the various interactions between proteins. Copurification is also used in the mapping of the interactome (the whole set of molecular interactions in cells) of a wide variety of living organisms.
Other purification techniques used in the study of biology and biochemistry include chromatography, which employs adsorption and desorption on a packed bed of a specific solid matter in order to purify various components of one feedstream.
This category contains scientific information on copurification, a specific process of physical separation, using either chromatography or one of the many purification techniques.
Konigsberg W.H., 1984: Photochemical cross linking of the escherichia coli single stranded dna binding protein to oligodeoxynucleotides identification of phenylalanine 60 as the site of cross linking. Journal Of Biological Chemistry7: 10850-10856 The single-stranded Dna-binding proteins from bacteriophage T4, F plasmid, E. coli and calf thymus can all be convalently cross-linked in vitro to thymine [...]
Funder J.W., 1986: Photoaffinity labeling of androgen receptors from human foreskin and cultured genital fibroblasts with tritiated methyltrienolone r 1881. Journal Of Steroid Biochemistry: 355-358 Androgen receptors were partially purified by affinity chromatography of cytosols prepared from either normal foreskin or normal cultured fibroblasts. Partially purified receptors were covalently labelled with R1881 (tritiated methyltrienolone) by [...]
Rhoads R.E., 1987: Phosphorylation site of eukaryotic initiation factor 4e. Journal Of Biological Chemistry2: 10434-10437 Eukaryotic protein synthesis initiation factor 4e (eIF-4e) was labeled in situ with orthophosphate in cultured HeLa cells and rabbit reticulocytes and purified by affinity chromatography. Tryptic digestion yielded one labeled peptide which contained predominantly serine and lysine. After treatment of [...]
Cooke R., 1979: Phosphorylation of uterine smooth muscle myosin permits actin activation. Journal Of Biochemistry (tokyo): 1489-1491 Myosin was purified from ovine uterine smooth muscle. The 20,000 dalton myosin L chain was phosphorylated to varying degrees by an endogenous Ca2+ dependent kinase. The kinase and endogenous phosphatases were then removed via column chromatography. Without actin [...]
Traugh J.A., 1985: Phosphorylation of the insulin receptor by casein kinase i. Journal Of Cellular Biochemistry: 159-170 Insulin receptor was examined as a substrate for the multipotential protein kinase casein kinase Casein kinase I phosphorylated partially purified insulin receptor from human placenta as shown by immunoprecipitation of the complex with antiserum to the insulin receptor. [...]
Hosey M.M., 1986: Phosphorylation of the cardiac muscarinic receptor in intact chick heart and its regulation by a muscarinic agonist. Journal Of Biological Chemistry7: 12429-12433 We have tested the possibility that regulation of cardiac muscarinic receptor function may involve receptor phosphorylation. Chick heart muscarinic receptors were purified from relatively small amounts of tissue to near [...]
Soderling T.R., 1985: Phosphorylation of sites 3 and 2 in rabbit skeletal muscle glycogen synthase by a multifunctional protein kinase atp citrate lyase kinase. Journal Of Biological Chemistry2: 12287-12292 A multifunctional protein kinase, purified from rat liver as Atp-citrate lyase kinase, has been identified as a glycogen synthase kinase. This kinase catalyzed incorporation of up [...]
Moudgil V.K., 1985: Phosphorylation of rat liver glucocorticoid receptor. Journal Of Biological Chemistry: 3684-3690 Rat liver glucocorticoid-receptor complex (GRc) was purified 2000-fold by a combination of methods including (Nh4)2so4-fractionation and phosphocellulose and Dna-cellulose chromatography. The purified glucocorticoid receptor preparation contained a major peptide of Mw = 90,000 and the GRc sedimented as 4 S in [...]
“Soderling T., 1987: Phosphorylation of purified rat striatal tyrosine hydroxylase by calcium calmodulin dependent protein kinase ii effect of an activator protein. Journal Of Neurochemistry: 1241-1249 The phosphorylation of tyrosine hydroxylase, purified from rat striatum, was investigated using purified Ca2+/calmodulin (CaM)-dependent protein kinase I This kinase catalyzed the Ca2+-dependent incorporation of up to 0.8 mol [...]
Schwartz E.R., 1984: Phosphorylation of proteoglycans from human articular cartilage. Arthritis & Rheumatism: 58-71 Previous studies showed that sulfated proteoglycans from human articular and epiphyseal cartilage were phosphorylated. These macromolecules contribute to the stiffness and resiliency of this tissue. This paper demonstrates that the phosphate moieties are an integral part of proteoglycan subunits. Specifically, evidence [...]