Peptides table

Like all neuropeptides, NT is synthesized as part of a larger precursor that also contains neuromedin N (NN), a 6 amino acid neurotensin-like peptide (Table 1). Pro-NT/NN is processed in the regulated secretory pathway of neuroendocrine cells by prohormone convertases PCI, PC2 and PC5-A that belong to a larger family of proprotein convertases. Due to differential cleavage specificity and tissue distribution of the convertases, pro-NT/NN processing gives rise to approximately a 1 1 and a 5 1 ratio of NT over NN content in the brain and gut, respectively. The peptides are stored in secretory vesicles and released from neuroendocrine cells in a Ca2+-dependent manner. NT and NN actions are terminated by desensitization of the... 

A5 and C primarily project to lamina II and V of the dorsal horn, where they synapse onto local interneurons or directly onto upward-projecting neurons (figure 8.1). These primary afferents release a number of neurotransmitters to relay pain, including glutamate, aspartate, substance P, neurokinin A and B, and calcitonin gene-related peptide (table 8.1). NMDA, non-NMDA and neurokinin receptors are involved in re-... 

Included in this category of compounds are one example of a substrate analogue containing an 7V-ketoalkyl scissile bond surrogate moiety (213), and a number of non-substrate analogue peptides Table 8.19) [176, 209-214]. Some of the latter compounds contain a Cys residue whose side-chain may be interacting with the active site Zn(II) atom. All of these compounds are... 

Three families of endogenous opioid peptides have been described in detail the endorphins, the pentapeptide enkephalins methionine-enkephalin (met-enkephalin) and leucine-enkephalin (leu-enkephalin), and the dynorphins. The three families of opioid receptors have overlapping affinities for these endogenous peptides (Table 31-1). 

At present, in addition to acetylcholine, glutamate, and y-aminobutyrate (GABA), glycine, noradrenaline (norepinephrine), and dopamine and 5-hydroxytryptamine (serotonin) are regarded as established transmitters. Other probable (putative) or possible candidate transmitters are also known. Aspartate, taurine, and a large number of peptides (Tables 30-1,30-4) are under consideration. 

Interestingly, the high a-helix propensity of (5)-ll has been observed in the X-ray structures of both tripeptides (see Table 1) and 9-mer peptides (Table 2). The molecular structures of the terminally blocked 9-mer peptides 31 and 32 were determined by X-ray diffraction and the observed < >P angles are shown in Table 2. For comparison, the similar peptide containing Aib at position 2 (30) is also listed in Table 2. In all three peptides, the succession of similar pairs of / F values correspond to an a-helical conformation. 

Most of the known bioactive peptides derived from milk proteins are opioid peptides (Table V). Those derived from caseins are called casomorphins or casoxins, while those from whey proteins are lactorphins, lactoferroxins or serorphin. Major opioid peptides are fragments of (3-casein. 

Syntheses, Conformation, and Reactions of Cyclic Peptides Table 10. (continued)... 

However, poor quality products were found whether reagent K or B was used and with either work-up procedure. Thus, although specific protocols for wtnk-up of crude products was requested from each participating laboratory, correlation of modifications with woik-up protocols could not be made. There was also no correlation between the age of reagents used and the quality of peptide products. One of the 2 Boc-synthesized products contained dehydrated peptides (Table III), which was a significant problem for Boc-synthesized peptides in prior stupes (1,3). It is important to note that the detection limit for non-desired products was quite low (5%), and that most samples contained large amounts of the desired peptide in the presence of non-desired peptides (Table II). 

Figure 3. MALDI mass spectrum of the total supernatant from the tryptic digest of the H,K-ATPase-enriched tubulovesicles. The H,K-ATPase was digested with tiypsin and the vesicles centrifuged to separate supernatant from the pellet. An aliquot of the supernatant was analyzed by MALDl/MS in the reflectron ion mode using a-cyano 4-hydroxy cinnamic acid as a matrix. The signals are denoted by numbers and were assigned to a-subunit peptides (Table 1).

The inertness of the nitrogen chemical shift of the NHf moiety to the state of the carboxyl group has been shown for a number of amino acids (95) (Table XII, note c). The entire range of occurrence of NHf and NH2 signals is about +335 to +365 ppm (Tables XII and XIII). The data on some simple dipeptides (74) indicate that the amino resonance can prove useful as a means of identification of N-terminal residues in the peptides (Table XIII). 

Hydrolysis of carboxylic and phosphoric esters is also a slow process at neutral pH, and is catalyzed by acids and bases by mechanisms similar to those involved in amide and peptide hydrolysis. Metal ions are also good catalysts of both carboxylic and phosphoric ester hydrolysis, typically with rate increases much higher than those observed for hydrolysis of amides or peptides (Table... 

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