Home
Resources
Publications
Characterization of Two High Molecular Weight Catechol-Containing Glycoproteins From Pharate Pupal Cuticle of the Tobacco Hornworm, Manduca Sexta

Characterization of Two High Molecular Weight Catechol-Containing Glycoproteins From Pharate Pupal Cuticle of the Tobacco Hornworm, Manduca Sexta

B M Okot-Kotber, T D Morgan, T L Hopkins, K J Kramer

Insect Biochem Mol Biol. 1994 Sep;24(8):787-802.

PMID: 7981728

Abstract:

Two high molecular weight cuticular proteins (MSCP120 and MSCP246) were extracted in acidic guanidine hydrochloride solution from tanning abdominal cuticle of Manduca sexta pharate pupae and purified by size exclusion high performance liquid chromatography. The apparent molecular weights were ca. 120 and 246 kDa as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Both proteins contained high levels of glutamate/glutamine, glycine, serine, alanine and aspartate/asparagine. MSCP120 was enriched in histidine relative to MSCP246, but the reverse was true for valine and proline. Small quantities of beta-alanine and 3,4-dihydroxyphenylalanine (DOPA), as well as other catechols and carbohydrates, also were detected in the hydrolysates. The proteins became radiolabeled when [1-14C]-beta-alanine was injected into pharate pupae, presumably by the formation of adducts with N-beta-alanyldopamine metabolites during sclerotization. Mild acid hydrolysis released N-beta-alanylnorepinephrine and 3,4-dihydroxyphenylketoethanol from both proteins. Strong acid hydrolysis yielded predominantly 3,4-dihydroxyphenylketoethylamine (arterenone), but also DOPA and dopamine. The N-terminal amino acid sequences of the two cuticular proteins were dissimilar, and that of MSCP246 was more hydrophobic than MSCP120. Both of these proteins were glycosylated with glucose, N-acetylglucosamine and traces of N-acetylgalactosamine, and MSCP246 also contained galactose. These structural glycoproteins, which occur in cuticle undergoing sclerotization, apparently react post-translationally with quinonoid tanning agents to yield catecholamine-protein adducts. Small amounts of peptidyl DOPA probably are formed by hydroxylation of tyrosyl residues. Results from this study are consistent with the hypothesis that these catechol-containing glycoproteins participate in cross-linking reactions in M. sexta pupal cuticle during sclerotization.

Chemicals Related in the Paper:

Catalog Number	Product Name	CAS Number	Price
AP6000437	Glycine hydrochloride solution	6000-43-7	Price
AP6003050	L-Alanine hydrochloride solution	6003-05-0	Price
AP645352	L-Histidine hydrochloride solution	645-35-2	Price
AP7776343	L-Proline hydrochloride solution	7776-34-3	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: