Metabolism of proctolin, a pentapeptide neurotransmitter in insects

Quistad, Gary B.; Adams, Michael E.; Scarborough, Robert M.; Carney, Robert L.; Schooley, David A.

doi:10.1016/0024-3205(84)90490-9

Cited by 61 publications

(46 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The initial degradation pathway of proctolin in insects has been shown to involve dipeptidyl aminopeptidases found as circulating and membrane enzymes [9,11,12]. The first purification of a membrane DPP exhibiting proctolindegrading activity in cockroach confirms the previous results from proctolin hydrolysis.…”

Section: Discussionsupporting

confidence: 70%

“…By contrast, a neurohormonal function for proctolin is unlikely as it is rapidly degraded by soluble haemolymph peptidases [9][10][11].…”

mentioning

confidence: 99%

“…Moreover, the demonstration that proctolin can excite neurones of the ventral nerve cord ganglia [8] suggests a neuroeffector role in insect nervous system [3,4,7]. By contrast, a neurohormonal function for proctolin is unlikely as it is rapidly degraded by soluble haemolymph peptidases [9][10][11].In vitro studies using different insect tissue homogenates showed that soluble aminopeptidase and soluble dipeptidyl aminopeptidase (DPP) activities mediated the majority of the proctolin degradation [9]. Both enzyme activities were also measured in a lower range from unwashed membranes prepared from proctolin-rich tissues [9].…”

mentioning

confidence: 99%

“…In vitro studies using different insect tissue homogenates showed that soluble aminopeptidase and soluble dipeptidyl aminopeptidase (DPP) activities mediated the majority of the proctolin degradation [9]. Both enzyme activities were also measured in a lower range from unwashed membranes prepared from proctolin-rich tissues [9].…”

mentioning

confidence: 99%

“…Both enzyme activities were also measured in a lower range from unwashed membranes prepared from proctolin-rich tissues [9]. In those obtained from the hindgut of Schistocerca gregaria, a membrane DPP activity was finally identified as the major and initial degradation pathway of proctolin, liberating the N-terminal dipeptide Arg-Tyr and characterized by a low K m value of 0.15 mM for proctolin.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Purification, partial sequencing and characterization of an insect membrane dipeptidyl aminopeptidase that degrades the insect neuropeptide proctolin

Mazzocco¹,

Fukasawa

Raymond³

et al. 2001

European Journal of Biochemistry

View full text Add to dashboard Cite

Two proctolin-binding proteins solubilized from 1600 cockroach hindgut membranes were purified 1000-fold using five chromatography steps. Twenty-five micrograms of protein were recovered from the final size-exclusion chromatography as a single peak eluting at 74 kDa, whereas two major bands at 80 and 76 kDa were identified after silver staining of electrophoresis gels. The fragments, sequenced by tandem mass spectrometry and the Edman method, revealed a high homology with rat liver dipeptidyl aminopeptidase (DPP) III and a significant homology between the cockroachpurified proteins. From analysis of the Drosophila genome sequence database, it was possible to identify a putative DPP sharing high homology with the sequences obtained from the cockroach purified proteins and with the rat DPP III.Anti-(rat liver DPP III) Ig reacted specifically with both cockroach-purified proteins in Western blot analysis. The purified proteins removed the N-terminal dipeptide from the insect myotropic neuropeptide proctolin (Arg-Tyr-Leu-ProThr) with a K m value of 3.8^1.1 mM. The specific DPP III inhibitor tynorphin prevented the degradation of proctolin by the purified insect DPP (IC 50 ¼ 0.68 mM). These results provide strong evidence that the cockroach-purified proteins represent an insect membrane DPP, presumably present in Drosophila, and that it is closely related to vertebrate DPP III.Keywords: dipeptidyl aminopeptidase; enkephalinase; insect; neuropeptide; proctolin.Proctolin (Arg-Tyr-Leu-Pro-Thr) was the first neuropeptide isolated and characterized in insects [1]. This neuropeptide has been detected throughout the nervous system of insects [2][3][4] and identified in neurones with a widespread distribution within the central nervous system of arthropods [2][3][4][5]. Proctolin is considered to have a neurotransmitter/ neuromodulator role in visceral and skeletal muscles [1,3,4,6,7]. Moreover, the demonstration that proctolin can excite neurones of the ventral nerve cord ganglia [8] suggests a neuroeffector role in insect nervous system [3,4,7]. By contrast, a neurohormonal function for proctolin is unlikely as it is rapidly degraded by soluble haemolymph peptidases [9][10][11].In vitro studies using different insect tissue homogenates showed that soluble aminopeptidase and soluble dipeptidyl aminopeptidase (DPP) activities mediated the majority of the proctolin degradation [9]. Both enzyme activities were also measured in a lower range from unwashed membranes prepared from proctolin-rich tissues [9]. In those obtained from the hindgut of Schistocerca gregaria, a membrane DPP activity was finally identified as the major and initial degradation pathway of proctolin, liberating the N-terminal dipeptide Arg-Tyr and characterized by a low K m value of 0.15 mM for proctolin. The concomitant presence of a membrane aminopeptidase that degrades the former ArgTyr dipeptide was also demonstrated in these preparations. In a further study, an aminopeptidase activity exhibiting a K m value of 23 mM was shown to be located mainly within...

show abstract

Section: Discussionsupporting

confidence: 70%

“…By contrast, a neurohormonal function for proctolin is unlikely as it is rapidly degraded by soluble haemolymph peptidases [9][10][11].…”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Purification, partial sequencing and characterization of an insect membrane dipeptidyl aminopeptidase that degrades the insect neuropeptide proctolin

Mazzocco¹,

Fukasawa

Raymond³

et al. 2001

European Journal of Biochemistry

View full text Add to dashboard Cite

show abstract

Proctolin, an insect neuropeptide

Konopińska

Rosiński²

1999

J. Peptide Sci.

View full text Add to dashboard Cite

show abstract

Degradation of the neuropeptide proctolin by membrane bound proteases of the hindgut and ovary of Locusta migratoria and the effects of different inhibitors

Puiroux

Loughton

1992

Arch Insect Biochem Physiol

View full text Add to dashboard Cite

Proctolin was incubated in vitro with crude membrane preparations derived from hind gut and ovary of Locusta rnigratoria. The metabolites of proctolin were separated and identified by reversed phase-high performance liquid chromatography which allowed the determination of the time course of degradation.At pHs 9.2 and 7.4, aminopeptidase activity predominated but some evidence of a carboxypeptidase could be inferred. At pH 6, aminopeptidase activity was slightly reduced compared to the level of aminopeptidase activity at the two former pHs; by contrast the carboxypeptidase was more important. At this pH, the presence of a membrane bound endopeptidase was detected.Phenanthroline, actinonin, amastatine, bestatin, and (2S,3R)-3-amino-2-hydroxy-4-(4-nitrophenyl)-butanoyl-L-leucine (HNBL) were tested at the concentration of 0.1 mM at pHs 8.2 and 6 and their ability to prevent the degradation of proctolin was estimated. A both pHs, HNBL and amastatin were revealed to be the most efficient inhibitors (SO to 75% inhibition) and o-phenanthroline appeared particularly efficacious at pH 6 (70% inhibition), whereas it was relatively poor inhibitor at pH 8.2. Furthermore, the use of these inhibitors confirmed the importance of carboxypeptidase activity at pH 6. These data are the first to describe proctolin degradation in ovary and hindgut muscle, important targets of proctolin action.

show abstract

Metabolism of proctolin, a pentapeptide neurotransmitter in insects

Cited by 61 publications

References 19 publications

Purification, partial sequencing and characterization of an insect membrane dipeptidyl aminopeptidase that degrades the insect neuropeptide proctolin

Purification, partial sequencing and characterization of an insect membrane dipeptidyl aminopeptidase that degrades the insect neuropeptide proctolin

Proctolin, an insect neuropeptide

Degradation of the neuropeptide proctolin by membrane bound proteases of the hindgut and ovary of Locusta migratoria and the effects of different inhibitors

Contact Info

Product

Resources

About