Dolichol phosphorylation occurs via a CTP‐dependent reaction in <i>Artemia</i> larvae

Horst, Michael N.

doi:10.1002/jez.1402520104

Cited by 5 publications

References 20 publications

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Concurrent protein synthesis is required for in vivo chitin synthesis in postmolt blue crabs

Horst

1990

J. Exp. Zool.

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Chitin synthesis in crustaceans involves the deposition of a protein-polysaccharide complex at the apical surface of epithelial cells which secrete the cuticle or exoskeleton. The present study involves an examination of in vivo incorporation of radiolabeled amino acids and amino sugars into the cuticle of postmolt blue crabs, Callinectes sapidus. Rates of incorporation of both 3H leucine and 3H threonine were linear with respect to time of incubation. Incorporation of 3H threonine into the endocuticle was inhibited greater than 90% in the presence of the protein synthesis inhibitor, puromycin. Linear incorporation of 14C glucosamine into the cuticle was also demonstrated; a significant improvement of radiolabeling was achieved by using 14C-N-acetylglucosamine as the labeled precursor. Incorporation of 3H-N-acetylglucosamine into the cuticle of postmolt blue crabs was inhibited 89% by puromycin, indicating that concurrent protein synthesis is required for the deposition of chitin in the blue crab. Autoradiographic analysis of control vs. puromycin-treated crabs indicates that puromycin totally blocks labeling of the new endocuticle with 3H glucosamine. These results are consistent with the notion that crustacean chitin is synthesized as a protein-polysaccharide complex. Analysis of the postmolt and intermolt blue crab cuticle indicates that the exoskeleton contains about 60% protein and 40% chitin. The predominant amino acids are arginine, glutamic acid, alanine, aspartic acid, and threonine.

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Concurrent protein synthesis is required for in vivo chitin synthesis in postmolt blue crabs

Horst

1990

J. Exp. Zool.

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Lipids

Urich¹

1994

Comparative Animal Biochemistry

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Isolation of a crustaceann-acetyl-d-glucosamine-1-phosphate transferase and its activation by phospholipids

Horst

1990

J Comp Physiol B

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The N-acetyl-D-glucosamine-1-phosphate:dolichol phosphate transferase from Artemia has been partially purified and characterized. The enzyme is solubilized from crude microsomes using Triton X-100, and after detergent removal appears to be associated with phospholipids. Using dolichol phosphate and UDP-N-acetyl-D-glucosamine as substrates, the enzyme catalyzes the formation of dolichol-pyrophosphate-N-acetyl-D-glucosamine. The product identity has been verified by TLC and paper chromatography following mild acid hydrolysis. Under the incubation conditions used only one product is made, i.e., Dol-P-P-GlcNAc. The formation of product is linear with increasing amounts of added protein and with time of incubation. The enzyme requires magnesium ions for activity. Activity of the enzyme is stimulated 6-fold by exogenous dolichol phosphate and is also stimulated by added phospholipids, with optimal activity being obtained in the presence of mixtures of phosphatidylcholine and phosphatidylglycerol. Enzymatic activity is not increased upon addition of GDP-mannose or dolichol phosphate mannose. The enzyme is rapidly inactivated by exposure to several detergents, including Triton X-100 and deoxycholate. The activity is inhibited by tunicamycin and by the purified B2 homologue of this antibiotic. Other antibiotic inhibitors such as diumycin and polyoxin D have little effect on the enzyme. Both the microsomal and solubilized enzyme preparations are inactivated by 70% upon treatment with phospholipase A2; activity may be restored by addition of phospholipids. Following hydrophobic interaction chromatography on Phenyl Sepharose, gel filtration chromatography on Sepharose CL-4B indicated that the enzyme, purified 81-fold, contained phophatidylcholine and phosphatidyl-ethanolamine.

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Dolichol phosphorylation occurs via a CTP‐dependent reaction in Artemia larvae

Cited by 5 publications

References 20 publications

Concurrent protein synthesis is required for in vivo chitin synthesis in postmolt blue crabs

Concurrent protein synthesis is required for in vivo chitin synthesis in postmolt blue crabs

Lipids

Isolation of a crustaceann-acetyl-d-glucosamine-1-phosphate transferase and its activation by phospholipids

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