Proteases digestivas do hepatopÃncreas dos camarÃes marinhos Farfantepenaeus subtilis e Farfantepenaeus paulensis

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Farfantepenaeus subtilis and Farfantepenaeus paulensis are native shrimp species and appear as an alternative to Litopenaeus vannamei cultivation, which represents more than 90% of the farmed shrimp in the Northeast of Brazil. Proteases from hepatopancreas of F. subtilis juveniles and adults and F. paulensis juveniles were studied according to the following properties: effect of inhibitors, optima pH and temperature, thermal stability, electrophoresis and zymograms. There are no significant differences on proteolytic activities between both life stages using azocasein, Leucine-p-nitroanilide (Leu-p-Nan) and aminoacyl-b-naphthylamide as substrates (p0.05). Trypsin-like (Benzoyl arginine p-nitroanilide - BapNA) and chymotrypsin-like (Succynil alanine alanine proline phenilalanine p-nitroanilide â SAPNA) activities were higher in F. subtilis juveniles than adults extracts (p<0.05). Trypsinlike and chymotrypsin-like activities were observed in crude extract of F. paulensis. Tosyllysine chloromethyl ketone (TLCK) and benzamidine inhibited proteolytic activity in F. subtilis and F. paulensis. Tosyl phenylalanine chloromethyl ketone (TPCK) was able to inhibit 59.34% of chymotryptic activity using SAPNA as substrate. The optimum temperature for trypsin-like and chymotrypsin-like activities for both life stages was 55ÂC, while for aminopeptidase activity there are a difference between juveniles (55ÂC) and adults (45ÂC). Trypsin retained about 15% of the initial activity when incubated at 55ÂC for 30 min while chymotrypsin-like and leucine aminopeptidase-like retained 60% and 45% of activity respectively. The optimum pH for trypsin-like was 8.0 and activity was maximum at 40ÂC on crude extract of F. paulensis. The highest chymotrypsin-like activity was obtained at alkaline pH range (7.2-9.0) at 55ÂC. The thermal stability zymogram of crude extract of F. subtilis showed a similar proteolytic band pattern between juvenile and adult shrimps, except that juvenile shrimps presented one proteolytic thermostable band at 65ÂC. PMSF strongly inhibited all proteolytic bands. Two possible thermal resistant (85ÂC) chymotrypsin isoforms (31.6 and 36.4 kDa) were found in F. paulensis. The characterization of digestive enzymes from native shrimps can provide relevant informations for understanding the physiology an the digestive abilities of these organisms. These enzymes are responsible for breaking down dietary proteins into aminoacids which are source of impotant monomers used for the synthesis proteins related to physiological events such as growth, reproduction and immunological response

ASSUNTO(S)

farfantepenaeus subtilis aminopeptidases farfantepenaeus paulensis aminopeptidases chymotrypsin bioquimica farfantepenaeus subtilis quimotripsina trypsin tripsina farfantepenaeus paulensis

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