Partial characterization of hepatopancreatic and extracellular digestive proteinases of wild and cultivated Octopus maya

Abstract

Proteinases from hepatopancreas (HP) and gastric juice (GJ) from wild and cultured red octopus (Octopus maya) were characterized. Hepatopancreas assays revealed optimal activity at pH 4, 9-10 and 10 for wild and pH 3, 8, and 9, for cultured octopuses, for total proteinases, trypsin and chymotrypsin, respectively. In the gastric juice, maximum activity was recorded at pH 6, 8, and 7 for total proteinases, trypsin, and chymotrypsin, respectively for both wild and cultured octopus. A reduction on enzyme activity of 70 and 20% was observed in HP and GJ extracts, respectively when protease inhibitor Pepstatin A was used. That result suggests that the main proteases in the HP were aspartic acid proteinases type (possibly Cathepsin D) and some of them were present in the GJ. Dissociating discontinuous polyacrylamide gel electrophoresis showed activity bands between 20 and 28, 30 and 34, 35 and 45, 60 and 70 kDa, and a last one between 75 and 100 kDa. We concluded that extracellular digestion of O. maya takes place in an acid environment, around pH 6. In contrast, intracellular digestion in the HP is developed at pHs between 3 and 4, where cathepsin D could be the most important enzyme for O. maya.

Timing of digestion, absorption and assimilation in octopus species from tropical (Octopus maya) and subtropical-temperate (O. mimus) ecosystems

“…Acidic proteases were several times more active than alkaline proteases in O. maya and O. mimus. This finding supports previous studies suggesting that the main role of acidic protease (presumably cathepsines) in octopus digestion is as extracellular digestive protease (Martínez et al 2011a(Martínez et al , 2012. We observed that GJ enzyme activity in O. maya exhibited several peaks throughout the digestive process, indicating that the release of digestive enzymes from the DG occurred in 2 pulses (Semmens 2002, Martínez et al 2012.…”

“…Activity of total acidic proteinases was evaluated using Stauffer's universal buffer (Stauffer 1989) prepared at pH 6 for GJ samples and pH 3 for DG samples (Martínez et al 2011a). Acidic proteinase and alkaline proteinase activities were assayed using hemoglobin (1%) or casein (1%) as the substrate (Anson 1938).…”

“…Our results suggest that the role of chyme as an activator of zymogens and other digestive processes can be extended at absorption sites, and can activate enzymes and reserve mobilization in the DG. With the first pulse of chyme, soluble proteins and amino acids could stimulate the brush wall of the cells in the octopus DG to absorb nutrients and activate endocytosis (Martínez et al 2011a). It is not known how these mechanisms operate in octopuses; however, in terrestrial animals some free AA can facilitate the absorption of other AA, depending on the metabolic relationship between them or if specific AA are pre-loaded in the intestine (Herzberg & Lerner 1973) and other nutrients to facilitate the absorption of the bulk of nutrients coming from the digestion of complex nutrients.…”

“…The chyme then moves directly from the Ce towards the DG, where intracellular digestion is carried out (Boucaud-Camou & Boucher-Rodoni 1983). The DG is the largest gland in the cephalopod body and performs many functions, such as synthesis and secretion of digestive enzymes, re-absorption and metabolism of nutrients, and synthesis and storage of glycogen (Boucaud-Camou et al 1976, Rosa et al 2005b, Martínez et al 2011a.…”

“…Digestive enzymes in O. vulgaris are released by apocrine secretion into the lumen of the DG tubules where they are sent as zymogens to the digestive tract (Budelmann et al 1997, Semmens 2002, Martínez et al 2011a). Most of these enzymes are acidic, and are present in secretory lysosomes in octopods (e.g.…”