Beta nomenclature

The alpha and beta nomenclature has been convenient to classify structures which clearly contain a dopamine like fragment. Ignoring for the moment subtypes of receptors, it seems the data have generally supported the idea that the alpha rotameric form of dopamine is more important for emetic activity and activity at DA2 receptors, while the beta rotameric form is more essential for action at the renal DA receptor. Some Important exceptions to this generalization will be presented later. 

Costall et al. (21) have questioned the relevance of this alpha and beta nomenclature. These workers noted that many of the differences observed between dopamine congeners of the two types in eliciting peripheral and behavioral effects may be attributed to ability to penetrate into the CNS, differential distribution, and differing susceptibility to Inactivation by COMT or MAO. The question of relative potency In comparing alpha rotameric types with beta rotameric types Is heavily dependent on which type of bioassay is employed. This problem is compounded by the fact that a large number of novel dopamine agonist types have not been completely evaluated pharmacologically. Each laboratory seems to have a particular series of assays and it is seldom that a compound is examined in all relevant tests. 

An exopeptidase that can only degrade a dipeptide. Examples are carnosine dipeptidase I (MEROPS M20.006), which degrades carnosine (beta-Ala-His), and membrane dipeptidase (MEROPS Ml9.001), which is important in the catabolism of glutathione, degrading the dipeptides Cys-Gly. Dipeptidases are included in Enzyme Nomenclature sub-subclass 3.4.13. 

The nomenclature of zeolites is rather arbitrary and follows no obvious rules because every producer of synthetic zeolites uses his/her own acronyms for the materials. However, as mentioned before, at least the structure types of the different zeolites have a unique code. For example, FAU represents Faujasite-type zeolites, LTA Linde Type A zeolites, MFI Mobile Five, and BEA Zeolite Beta. The structure commission of the International Zeolite Association (IZA) is the committee granting the respective three-letter codes [4], Some typical zeolites, which are of importance as catalysts in petrochemistry, will be described in the following sections. 

There is no systematic nomenclature developed for molecular sieve materials. The discoverer of a synthehc species based on a characteristic X-ray powder diffraction pattern and chemical composihon typicaUy assigns trivial symbols. The early syn-thehc materials discovered by Milton, Breck and coworkers at Uruon Carbide used the modem Lahn alphabet, for example, zeoHtes A, B, X, Y, L. The use of the Greek alphabet was inihated by Mobil and Union Carbide with the zeoHtes alpha, beta, omega. Many of the synthetic zeoHtes which have the structural topology of mineral zeoHte species were assigned the name of the mineral, for example, syn-thehc mordenite, chabazite, erionite and offretite.The molecular sieve Hterature is replete with acronyms ZSM-5, -11, ZK-4 (Mobil), EU-1, FU-1, NU-1 (ICI), LZ-210, AlPO, SAPO, MeAPO, etc. (Union Carbide, UOP) and ECR-1 (Exxon). The one pubHcaHon on nomenclature by lUPAC in 1979 is Hmited to the then-known zeoHte-type materials [3]. 

Before this is closed, a couple of points need be made regarding nomenclature. Older literature uses alpha for the 2-position of the indole ring. Thus, alpha-methyltryptamine, in early literature, refers to the indole-2-methyl, not to a side-chain methyl derivative. Throughout TiHKAL, the numbers are devoted to the indole ring, and the alpha and beta terms to the side-chain. And the use of the letter N refers to the side-chain amino nitrogen atom. The pyrrole nitrogen is the indole position 1. 

Interferons were originally discovered as proteins that interfered with virus replication. When mice were injected with antibodies to interferons, they became markedly susceptible to virus-mediated disease, including virus-related tumour induction. Interferons can be detected at low levels in most human tissues, but amounts increase upon infection with viruses, bacteria, protozoa, and exposure to certain growth factors. Interferons were initially classified according to the cellular source, but recent nomenclature is based primarily on sequencing data. Thus leukocyte interferon (a mixture of proteins) is now known as interferon alfa, fibroblast interferon as interferon beta, and immune interferon as interferon gamma. 

Because of the incorporation of beta bonds directly into the nomenclature, for conjugated monocyclic compounds having molecular formula C2nH2n there is no need to add a declaration of odd vs. even in order to distinguish between compounds which are aromatic vs. anti-aromatic namely, when n is odd the compound is aromatic vs. when n is even it is anti-aromatic. This is spelled out directly in the nomenclature The bonds between carbon atoms of a monocyclic aromatic compound have bond order of 1.5 thus the compound is nomenclated by the formula... 

One of the main reasons why nodal nomenclature [42] was created was that the IUPAC organic nomenclature did not allow for assigning unique canonical names to members of the class of molecules referred to as "cyclophanes" a problem that would not have arisen had beta bonds been available. This is not to devalue the many virtues of nodal nomenclature, rather merely to show how the proposed system nomenclates these compounds without difficulty. 

As well as new properties of these molecules that have come to light with the discovery and nomenclating of the higher lullerenes and fulleranes, an extension that is unfathomable using traditional nomenclature, but is readily explained using beta bonds is next described when some of the carbon atoms are replaced by metal atoms in various of the smaller fullerenes. These molecules, which historically are not in the domain of... 

Ahlquist has attempted to explain the actions of the catecholamines in terms of two different types of adrenergic receptors. According to Ahlquist s nomenclature, alpha receptors generally mediate vasoconstriction and excitatory functions, while stimulation of the beta receptors produces vasodilation and other responses associated with smooth muscle relaxation Beta receptors are believed to mediate the chronotropic and inotropic action of catecholamines. Epinephrine is active on both alpha and beta receptors while the action of norepinephrine is primarily on the alpha sites. Isoproterenol has little action on alpha sites, being a potent stimulator of beta receptors. 

C. M. Wilmot, J. M. Thornton. Beta-turns and their distortions a proposed new nomenclature. Protein Eng. 1990,... 

---