Dynorphins characterization

Silberring, J., Castello, M. E., and Nyberg, F. (1992). Characterization of dynorphin A-converting enzyme in human spinal cord. An endoprotease related to a distinct conversion pathway for the opioid heptadecapeptide J. Biol. Chem. 267, 21324—21328. 

As an instrumental approach to conventional electrophoresis, capillary electrophoresis offers the capability of on-line detection, micropreparative operation and automation (6,8,45-47). In addition, the in tandem connection of capillary electrophoresis to other spectroscopy techniques, such as mass spectrometry, provides high information content on many components of the simple or complex peptide under study. For example, it has been possible to separate and characterize various dynorphins by capillary electrophoresis-mass spectrometry (33). Therefore, the combination of CE-mass spectrometry (CE-MS) provides a valuable analytical tool useful for the fast identification and structural characterization of peptides. Recently, it has been demonstrated that the use of atmospheric pressure ionization using Ion Spray Liquid Chromatography/ Mass Spectrometry is well suited for CE/MS (48). This approach to CE/MS provides a very effective and straightforward method which allow the feasibility of obtaining CE/MS data for peptides from actual biological extracts, i.e., analysis of neuropeptides from equine cerebral spinal fluid (33). 

It is evident that /3-LPT is not the sole source of endogenous opioid peptides found in the pituitary gland now that dynorphin, an active peptide isolated from this organ as early as 1975, has been characterized.(127) This peptide differs from the /3-endorphins (lower mol wt, more basic, more persistent effect in GPI assay, and resistant to CNBr) and its first 13 residues (established by a microsequencing technique) commence with Leu-enkephalin at the N-terminal. The absence of Met5 accounts for its insensitivity toward CNBr. The synthetic tridecapeptide (12, dynorphin 1-13) and dynorphin itself... 

Racz I, Bilkei-Gorzo A, Markert A, Stamer F, Gothert M, Zimmer A (2008) Anandamide effects on 5-HT3 receptors in vivo. Eur J Pharmacol 596 98-101 Rady JJ, Fujimoto JM (2002) Nociceptin and dynorphin A(l-17) produce antianalgesia trough independent systems in mice. Life Sci 70 1085-1093 Raffa RB, Schupsky JJ, Lee DKH, Jacoby HI (1996) Characterization of endotheUn-induced nociception in mice evidence for a mechanistically distinct analgesic model. J Pharmacol Exp Ther 278 1-7... 

Houghten RA. Tritiated porcine Dynorphin (1-17) synthesis and characterization. Life Sci. 1982 31 1805-1808. 

Spiny projection neurons all contain glutamic acid decarboxylase (GAD) the synthetic enzyme for the neurotransmitter GABA (Kita and Kitai 1988). In addition, most of those neurons projecting to the globus pallidus alone contain the neuropeptide enkephalin, whereas most of those which project to the substantia nigra contain the neuropeptides substance P and dynorphin (Beckstead and Kersey 1985 Gerfen and Young 1988 Haber and Watson 1983). Spiny projection neurons contain different complements of neurotransmitter receptors, and other proteins that serve to characterize particular subpopulations of striatal output neurons. These will be discussed in further detail below. 

Because of some of the problems with bioassays and immunoassays, liquid chromatography (LC)-based techniques are increasingly applied as an alternative. While modern LC-based assays have a comparable sensitivity to immunoassays, they oftentimes are characterized by a higher selectivity [18, 19]. Muller et ah, for example, used LC/mass spectrometry with matrix-assisted laser desorption ionization in ex vivo pharmacokinetic studies in combination with enzyme inhibition experiments to investigate the complex metabolism of dynorphin Al-13, a peptide with opioid activity, up to the fifth metabolite generation [20, 21]. 

Enkephalinase is not only involved in deactivation of the enkephalins but also in degradation of other peptides and hormones including Substance P, cholecystokinin, bradykinin, chemotactic peptide and atrial natriuretic factor (ANP) [67,69-72]. Peptides such as the dynorphins and )5-endorphin are not hydrolysed efficiently [73]. The specificity of the enzyme has been indirectly characterized by establishing the inhibitory potency of various peptides towards hydrolysis of H[Leu] -enkephalin [26]. 

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