Regulatory peptides in the respiratory system

Summary Many regulatory peptides have been described in the respiratory tract of animals and humans. Some peptides (bombesin, calcitonin, calcitonin gene-related peptide) are localised to neuroendocrine cells and may have a trophic or transmitter role. Others are localised to motor nerves. Vasoactive intestinal peptide and peptide histidine isoleucine are candidates for neurotransmitters of non-adrenergic inhibitory fibres and may be cotransmitters in cholinergic nerves. These peptides may regulate airway smooth muscle tone, bronchial blood flow and airway secretions. Sensory neuropeptides (substance P, neurokinin A and B, calcitonin gene-related peptide) may contract airway smooth muscle, stimulate mucus secretion and regulate bronchial blood flow and microvascular permeability. If released by an axon reflex mechanism these peptides may be involved in the pathogenesis of asthma. Other peptides, such as galanin and neuropeptide Y, are also present but their function is not yet known.     

Biology of the CAPA peptides in insects

CAPA peptides have been isolated from a broad range of insect species as well as an arachnid, and can be grouped into the periviscerokinin and pyrokinin peptide families. In insects, CAPA peptides are the characteristic and most abundant neuropeptides in the abdominal neurohemal system. In many species, CAPA peptides exert potent myotropic effects on different muscles such as the heart. In others, including blood-sucking insects able to transmit serious diseases, CAPA peptides have strong diuretic or anti-diuretic effects and thus are potentially of medical importance. CAPA peptides undergo cell-type-specific sorting and packaging, and are the first insect neuropeptides shown to be differentially processed. In this review, we discuss the current knowledge on the structure, distribution, receptors and physiological actions of the CAPA peptides. Received 28 April 2006; received after revision 5 June 2006; accepted 4 July 2006     

Mass spectrometric determination of the amino acid sequence in peptides: Desulfurization of sulfur-containing peptides

, N- 20 - .     

The prolactin releasing peptides: RF-amide peptides

Although dopamine is considered the major hypothalamic controller of prolactin release from the anterior pituitary gland, there is evidence that a yet to be discovered prolactin releasing factor (PRF) also exists in brain. Recently, two peptides were isolated, products of the same prohormone, that were reported to have significant prolactin-releasing activity. These peptides, called prolactin releasing peptides, are not accepted by all investigators to be in fact PRFs. Instead, it appears that their widespread distribution in brain and the presence of receptors for the peptides in sites unrelated to neuroendocrine function are the basis for a variety of central nervous system action including activation of the autonomic nervous system. Thus, these peptides may not be PRFs, but instead neuroactive agents that are involved in many brain circuits with divergent functions.     

On the origin ofd-aminoacid residues in microbial peptides

Zusammenfassung Ein Gemisch von Angolid und seinen drei valinhaltigen Homologen ausl-valinhaltiger Kultur vonPithomyces sacchari enthielt gleiche Mengen zweier Isomere mit nur einem Valinrest, was wahrscheinlich macht, dass Angolid durch Umkehrung einesl-Rests aus einem zyklisch-symmetrischen Vorläufer entsteht.

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This investigation was supported by a grant No. MA 2480 from the Medical Research Council of Canada. We are most grateful to Dr.J. A. Verpoorte for the aminoacid analyses.     

Synthetic peptides related to eledoisin. Physalaemin-like peptides

Riassunto Vengono riportate le proprietà di una serie di peptidi sintetici affini per struttura alla fisalemina.     

Steroidal peptides

Zusammenfassung Es wird die Möglichkeit erwogen, dass Steroide mit geeignet gebauten Peptidseitenketten am Aufbau oder Transport von Hormonen beteiligt sein könnten. Über die erstmalige Darstellung von Steroidpeptiden wird berichtet. Als Beispiele werden die Synthesen der beiden geschützten Steroidpeptide III und IV beschrieben.

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Part XXIV of a series entitledSteroids and Related Natural Products. For the preceding contribution see:J. P. Kutney, W. Cretney, G. R. Pettit, andJ. C. Knight, Tetrahedron, in press.

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A preliminary report of this study was presented (April 9, 1964) at the Third International Symposium on the Chemistry of Natural Products, Kyoto (Japan).

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This investigation was supported by National Science Foundation Research Grant GB-249.     

Regulatory mechanisms involved in modulating RGS function

Regulator of G-Protein Signaling (RGS) refers to a conserved 120–125 amino acid motif that was first identified by its ability to negatively regulate G-Protein-Coupled Receptor (GPCR) signalling. Mechanistically, RGSs were found to regulate GPCR responses by binding to and stimulating the GTPase activity of the receptor-activated GTP-bound G α subunits. There are now over 25 mammalian RGSs containing proteins that are reported to carry out a variety of functions, many of which are unrelated to GPCR signalling. RGS proteins range in size from small proteins that contain little more than an RGS box to very large proteins that contain a variety of domains. The selectivity of function of the RGS proteins is attributable to the divergence of the RGS sequences as well as the presence of a variety of functional motifs, which allow them to interact with other proteins. Here we focus on the RGSs that are involved in modulating GPCR signalling by reviewing the diversity of the mechanisms involved in regulating these RGSs. Received 9 February 2006; received after revision 4 May 2006; accepted 22 May 2006     

Regulatory properties of the citrate synthase fromRhodospirillum rubrum

Summary Citrate synthase, purified 600-fold fromRhodospirillum rubrum, is activated by KCl and inhibited by ATP and NADH; the effect of the latter inhibitor is completely counteracted by AMP and partially counteracted by KCl.This work was supported by grants from the Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina and the Consejo de Investigaciones de la Universidad Nacional de Rosario. JJC, and EM and AIH, are members of the Carrera del Investigador Cientifico of the former and the latter institutions, respectively.