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Carboxypeptidase B was purified from the pyloric ceca of the starfish Asterias amurensis. The final enzyme preparation was nearly homogeneous in polyacrylamide gel electrophoresis and its molecular weight was estimated as approximately 34,000. The optimum pH and temperature of the enzyme for hydrolysis of benzoyl-glycyl-L-arginine were at approximately pH 7.5 and 55 degrees C, respectively. The enzyme was unstable at above 50 degrees C and at below pH 5.0. The enzyme was activated by Co(2+), but was inhibited by EDTA and Hg(2+). The N-terminal amino acid sequence of A. amurensis carboxypeptidase B was ASFDYNVYHSYQEIMNWITN.

Trypsin was purified from pyloric ceca of the starfish Asterina Pectinifera by ammonium sulfate precipitation, gel filtration, and cation-exchange chromatography. Final enzyme preparation was nearly homogeneous in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and its molecular weight was estimated as approximately 28000. Optimum pH and temperature of A. pectinifera trypsin for hydrolysis of N(alpha)-p-Tosyl-L-arginine methyl ester hydrochloride were approximately pH 8.0 and 55 degrees C, respectively. A. pectinifera trypsin was unstable at above 50 degrees C and below pH 5.0, and was not activated by adding Ca(2+). The N-terminal amino acid sequence of A. pectinifera trypsin, IVGGHEF, was found.

Abstract: Carboxypeptidase B was purified from the pyloric ceca of the starfish, Asterina pectinifera. The final enzyme preparation was nearly homogeneous in sodium dodecyl sulfate–polyacrylamide gel electrophoresis and its molecular weight was estimated as approximately 34,000. The value of the specificity constant (k cat/K m) for hydrolysis of benzoyl-glycyl-l-arginine by the purified enzyme was 1.72×105 M−1 s−1. The optimal pH and the optimal temperature of the enzyme were pH 7.5 and 55°C, respectively. The enzyme was unstable above 50°C and below pH 5.0. The enzyme was activated by Co2+, and inhibited by EDTA. The N-terminal amino acid sequence of the enzyme was determined as ATFDYNKYHSYQEIMDWVTN. [Copyright &y& Elsevier]

Abstract: Phospholipase A (PLA) activities in the pyloric ceca and viscera from seven species of marine invertebrates (four starfish, one sea urchin, and two shellfish) were determined. Relatively high PLA specific activities were found in the pyloric ceca of two species of starfish (Coscinasterias acutispina and Plazaster borealis). Phospholipase A2s (PLA2s) were partially purified from the pyloric ceca of the starfish, C. acutispina PLA2 (C-PLA2) and P. borealis PLA2 (P-PLA2). The C-PLA2 and P-PLA2 mainly released oleic acid from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine. Temperature optima of the C-PLA2 and P-PLA2 were at around 60 °C and 50 °C, respectively, and pH optima of the C-PLA2 and P-PLA2 were both at around pH 10.0. The activities of the C-PLA2 and P-PLA2 were enhanced by sodium deoxycholate and 1 mM or higher concentration of Ca2+. The C-PLA2 and P-PLA2 did not show the fatty acid specificity for hydrolysis of phosphatidylcholine. Unlike porcine pancreatic PLA2, the C-PLA2 and P-PLA2 hydrolyzed phosphatidylcholine more effectively than phosphatidylethanolamine. [Copyright &y& Elsevier]

SUMMARY:The complete amino acid sequence of phospholipase A2 (PLA2) from the pyloric ceca of the starfish Asterina pectinifera was determined by automated Edman degradation. The A. pectinifera PLA2 (APLA2) consists of 137 amino acids with an unblocked N-terminus and its molecular weight is calculated to be 15 300.1. The enzyme contains 14 cysteine (Cys) residues at the corresponding positions of the same residues which have been shown to be involved in intramolecular disulfide bonds in mammalian pancreatic PLA2. The region involving an active site and a Ca2+-binding loop shows fairly high sequence homology (75%) between the APLA2 and porcine pancreatic PLA2. The APLA2 conserved the amino acid sequence of the loop portion of the porcine pancreatic PLA2 except for the deletion of two amino acids. These features indicate that the APLA2 can be classified into the group 1 type PLA2. In contrast, the homology between the APLA2 and porcine pancreatic PLA2 was calculated to be 47% in the whole region. Further, the insertion of sixteen residues and the deletion of three residues were required in the sequence of the APLA2 to align the corresponding region to the β-wing of porcine pancreatic PLA2. These differences in amino acid sequence of the APLA2 may account for its specific properties such as the higher activity and the characteristic substrate specificity. [ABSTRACT FROM AUTHOR]

Presents information on mammalian pancreatic trypsin, a serine protease synthesized by acinar cells. Assessment of enzymes contained in it; Analysis of trypsin-like enzymes from starfish; Overview of the alignment of amino acid sequences of starfish.