Reversible activation of prophenoloxidase with 2‐propanol in Drosophila melanogaster

Asada, Nobuhiko

doi:10.1002/(sici)1097-010x(199809/10)282:1/2<28::aid-jez6>3.3.co;2-u

Cited by 23 publications

(29 citation statements)

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“…detergents and alcohols) or polypeptides (e.g. antimicrobial peptides, serine proteinase precursors) (Asada et al, 1993;Decker et al, 2001;Nagai et al, 2001;Nagai and Kawabata, 2000), PAP-1 and SPHs could simply bind to proPO, change its conformation, and yield PO activity without any proteolysis. To test this possibility, we first incubated PAP-1 with an irreversible serine proteinase inhibitor, APMSF, to block its amidase activity.…”

Section: Significance Of Proteolytic Cleavage In Propo Activationmentioning

confidence: 92%

Manduca sexta prophenoloxidase (proPO) activation requires proPO-activating proteinase (PAP) and serine proteinase homologs (SPHs) simultaneously

Gupta

Wang

Jiang

2005

Insect Biochemistry and Molecular Biology

103

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In the tobacco hornworm Manduca sexta, proteolytic activation of prophenoloxidase (proPO) is mediated by three proPO-activating proteinases (PAPs) and two serine proteinase homologs (SPHs) (Proceedings of the National Academy of Sciences, USA 95 (1998) (2004) 731-742), roles of these clip-domain proteins (i.e. PAPs and SPHs) in proPO activation are poorly defined. To better understand this process, we further characterized the activation reaction using proPO, PAP-1 and SPHs. PAP-1 itself cleaved nearly 1/3 of proPO at Arg 51 without generating much phenoloxidase (PO) activity. In the presence of SPHs, the cleavage of proPO became more complete while the increase in PO activity was over 20-fold, indicating that the extent of cleavage does not directly correlate with PO activity. Since SPHs and p-amidinophenyl methanesulfonyl fluoride (APMSF)-treated PAP-1 did not generate active PO by interacting with proPO, proteolytic cleavage is critical for proPO activation. After 1/5 of proPO was processed by PAP-1 alone which was then inactivated by M. sexta serpin-1J or APMSF, further incubation of the reaction mixture with SPHs failed to generate active PO either. Thus, SPHs cannot generate PO activity by simply binding to cleaved proPO. M. sexta proPO activation requires active PAP-1 and SPHs at the same time-one for limited proteolysis and the other as a cofactor, perhaps. Gel filtration chromatography and native gel electrophoresis revealed the PAP-SPH, proPO-PAP, and SPH-proPO associations, essential for generating high M r , active PO at the site of infection.

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Section: Significance Of Proteolytic Cleavage In Propo Activationmentioning

confidence: 92%

Manduca sexta prophenoloxidase (proPO) activation requires proPO-activating proteinase (PAP) and serine proteinase homologs (SPHs) simultaneously

Gupta

Wang

Jiang

2005

Insect Biochemistry and Molecular Biology

103

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“…PO is present in almost all organisms, functioning as an initiator of melanin synthesis (4)(5)(6)(7). Several potential activators of PO activity in vivo have been identified such as fatty acids, phospholipids, detergents, small antimicrobial peptides, and alcohols (3,(8)(9)(10). SDS, an artificial activator, seems to mimic the natural activation of PO; however, the mode of this activation is not known.…”

Section: Introductionmentioning

confidence: 99%

Hemocyanin conformational changes associated with SDS-induced phenol oxidase activation

Baird

Kelly

Price

et al. 2007

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics

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The enzymatic activity of phenoloxidase is assayed routinely in the presence of SDS. Similar assay conditions elicit phenoloxidase activity in another type 3 copper protein, namely hemocyanin, which normally functions as an oxygen carrier. The nature of the conformational changes induced in type 3 copper proteins by the denaturant SDS is unknown. This comparative study demonstrates that arthropod hemocyanins can be converted from being an oxygen carrier to a form which exhibits phenoloxidase activity by incubation with SDS, with accompanying changes in secondary and tertiary structure. Structural characterisation, using various biophysical methods, suggests that the micellar form of SDS is required to induce optimal conformational transitions in the protein which may result in opening a channel to the di-copper centre allowing bulky phenolic substrates access to the catalytic site.

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“…The presence of a lag period and the lack of change of the molecular mass of the protein after activation could indicate a slow conformational change of the protein to render the final active form [25]. The activation of latent tyrosinase occurred by different treatments or agents such as SDS [26], fatty acids [27], alcohols [28] and proteases [29]. Aspergillus oryzae protyrosinase is inactive at neutral and alkaline pH, and is activated by acid treatment [30].…”

Section: Resultsmentioning

confidence: 99%

Dual effects of aliphatic carboxylic acids on cresolase and catecholase reactions of mushroom tyrosinase

Gheibi

Saboury

Haghbeen

et al. 2009

Journal of Enzyme Inhibition and Medicinal Chemistry

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Reversible activation of prophenoloxidase with 2‐propanol in Drosophila melanogaster

Cited by 23 publications

References 0 publications

Manduca sexta prophenoloxidase (proPO) activation requires proPO-activating proteinase (PAP) and serine proteinase homologs (SPHs) simultaneously

Manduca sexta prophenoloxidase (proPO) activation requires proPO-activating proteinase (PAP) and serine proteinase homologs (SPHs) simultaneously

Hemocyanin conformational changes associated with SDS-induced phenol oxidase activation

Dual effects of aliphatic carboxylic acids on cresolase and catecholase reactions of mushroom tyrosinase

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