Document Detail

Aspartic proteinases in the digestive tract of marine decapod crustaceans.
MedLine Citation:
PMID:  16788916     Owner:  NLM     Status:  MEDLINE    
Decapod crustaceans synthesize highly active proteolytic enzymes in the midgut gland and release at least a part of them into the stomach where they facilitate the first step in peptide hydrolysis. The most common proteinases in the gastric fluid characterized so far are serine proteinases, that is, trypsin and chymotrypsin. These enzymes show highest activities at neutral or slightly alkaline conditions. The presence of acid proteinases, as they prevail in vertebrates, has been discussed contradictorily yet in invertebrates. In this study, we show that acid aspartic proteinases appear in the gastric fluid of several decapods. Lobsters Homarus gammarus showed the highest activity with a maximum at pH 3. These activities were almost entirely inhibited by pepstatin A, which indicates a high share of aspartic proteinases. In other species (Panulirus interruptus, Cancer pagurus, Callinectes arcuatus and Callinectes bellicosus), proteolytic activities were present at acid conditions but were distinctly lower than in H. gammarus. Zymograms at pH 3 showed in each of the studied species at least one, but mostly two-four bands of activity. The apparent molecular weight of the enzymes ranged from 17.8 to 38.6 kDa. Two distinct bands were identified which were inhibited by pepstatin A. Acid aspartic proteinases may play an important role in the process of extracellular digestion in decapod crustaceans. Activities were significantly higher in clawed lobster than in spiny lobster and three species of brachyurans. Therefore, it may be suggested that the expression of acid proteinases is favored in certain groups and reduced in others.
María de Los Angeles Navarrete del Toro; Fernando García-Carreño; Manuel Díaz López; Laura Celis-Guerrero; Reinhard Saborowski
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of experimental zoology. Part A, Comparative experimental biology     Volume:  305     ISSN:  1548-8969     ISO Abbreviation:  J. Exp. Zoolog. Part A Comp. Exp. Biol.     Publication Date:  2006 Aug 
Date Detail:
Created Date:  2006-08-14     Completed Date:  2006-10-24     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  101168223     Medline TA:  J Exp Zool A Comp Exp Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  645-54     Citation Subset:  IM    
Copyright Information:
Copyright 2006 Wiley-Liss, Inc.
Centro de Investigaciones Biológicas del Noroeste (CIBNOR). P.O. Box 128 La Paz, B.C.S. 23000, México.
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MeSH Terms
Aspartic Acid Endopeptidases / analysis*,  metabolism*
Cysteine Proteinase Inhibitors / pharmacology
Decapoda (Crustacea) / enzymology*
Electrophoresis, Polyacrylamide Gel
Enzyme Activation / drug effects
Gastrointestinal Tract / enzymology
Hydrogen-Ion Concentration
Leucine / analogs & derivatives,  pharmacology
Pepstatins / pharmacology
Protease Inhibitors / pharmacology
Serine Proteinase Inhibitors / pharmacology
Tosyllysine Chloromethyl Ketone / pharmacology
Trypsin / pharmacology
Reg. No./Substance:
0/Cysteine Proteinase Inhibitors; 0/Pepstatins; 0/Protease Inhibitors; 0/Serine Proteinase Inhibitors; 2104-86-1/Tosyllysine Chloromethyl Ketone; 39324-30-6/pepstatin; 61-90-5/Leucine; 66701-25-5/E 64; EC; EC 3.4.23.-/Aspartic Acid Endopeptidases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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