Alicyclic hydrocarbons in which three or more of the carbon atoms in each molecule are united in a ring structure and each of the ring carbon atoms is joined to two hydrogen atoms or alkyl groups. The simplest members are cyclopropane (C3H6), cyclobutane (C4H8), cyclohexane (C6H12), and derivatives of these such as methylcyclohexane (C6H11CH3). (From Sax, et al., Hawley's Condensed Chemical Dictionary, 11th ed)
Combinatorial Chemistry Techniques
Group of alkaloids containing a benzylpyrrole group (derived from TRYPTOPHAN)
A continuous circle of peptide bonds, typically of 2-3 dozen AMINO ACIDS, so there is no free N- or C-terminus. They are further characterized by six conserved CYSTEINE residues that form CYSTINE KNOT MOTIFS.
Heterocyclic Compounds with 4 or More Rings
The excision of in-frame internal protein sequences (INTEINS) of a precursor protein, coupled with ligation of the flanking sequences (EXTEINS). Protein splicing is an autocatalytic reaction and results in the production of two proteins from a single primary translation product: the intein and the mature protein.
The collective name for the boron hydrides, which are analogous to the alkanes and silanes. Numerous boranes are known. Some have high calorific values and are used in high-energy fuels. (From Grant & Hackh's Chemical Dictionary, 5th ed)
Solid-Phase Synthesis Techniques
Techniques used to synthesize chemicals using molecular substrates that are bound to a solid surface. Typically a series of reactions are conducted on the bound substrate that results in either the covalent attachment of specific moieties or the modification of existing function groups. These techniques offer an advantage to those involving solution reactions in that the substrate compound does not have to be isolated and purified between the reaction steps.
Heterocyclic Compounds, 2-Ring
A homologous group of cyclic GLUCANS consisting of alpha-1,4 bound glucose units obtained by the action of cyclodextrin glucanotransferase on starch or similar substrates. The enzyme is produced by certain species of Bacillus. Cyclodextrins form inclusion complexes with a wide variety of substances.
The internal fragments of precursor proteins (INternal proTEINS) that are autocatalytically removed by PROTEIN SPLICING. The flanking fragments (EXTEINS) are ligated forming mature proteins. The nucleic acid sequences coding for inteins are considered to be MOBILE GENETIC ELEMENTS. Inteins are composed of self-splicing domains and an endonuclease domain which plays a role in the spread of the intein's genomic sequence. Mini-inteins are composed of the self-splicing domains only.
Cystine Knot Motifs
Amino acid sequence in which two disulfide bonds (DISULFIDES) and their connecting backbone form a ring that is penetrated by a third disulfide bond. Members include CYCLOTIDES and agouti-related protein.
Magnetic Resonance Spectroscopy
Compounds with a core of 10 carbons generally formed via the mevalonate pathway from the combination of 3,3-dimethylallyl pyrophosphate and isopentenyl pyrophosphate. They are cyclized and oxidized in a variety of ways. Due to the low molecular weight many of them exist in the form of essential oils (OILS, VOLATILE).
Organic nitrogenous bases. Many alkaloids of medical importance occur in the animal and vegetable kingdoms, and some have been synthesized. (Grant & Hackh's Chemical Dictionary, 5th ed)
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Glycogen Debranching Enzyme System
1,4-alpha-D-Glucan-1,4-alpha-D-glucan 4-alpha-D-glucosyltransferase/dextrin 6 alpha-D-glucanohydrolase. An enzyme system having both 4-alpha-glucanotransferase (EC 126.96.36.199) and amylo-1,6-glucosidase (EC 188.8.131.52) activities. As a transferase it transfers a segment of a 1,4-alpha-D-glucan to a new 4-position in an acceptor, which may be glucose or another 1,4-alpha-D-glucan. As a glucosidase it catalyzes the endohydrolysis of 1,6-alpha-D-glucoside linkages at points of branching in chains of 1,4-linked alpha-D-glucose residues. Amylo-1,6-glucosidase activity is deficient in glycogen storage disease type III.