Preliminary Studies On Histology Of Digestive System And Physical-Chemical Characters Of Trpsin-like Enzyme From Neomysis Japonica

Neomysis japonica belongs to Crustacea, which widely distribute along coastwise of Bohai sea and Yellow sea. It is a kind of benthic and omnivorous animal which can reproduce several times during a year. People living along the seashore of China, Japan and India make use of it as food or for fowl and fish' s feedingstuff. Mysis has been cultured artificially as feedingstuff at present.Neomysis japonica cultured in laboratory easily autolyze half an hour after their death. So there may be a efficient digestive enzymes system in them as same as in Antarctic krill' s.Krill enzymes are now being exploited for medical applications , such as debridement of necrotic wounds and laundry detergents. Some reseach result indicate that trypsin attained from vertebrate and proteinases distilled from microorganism can be utilized to for exploiding and utilising low worth protein of fish Crustacea and mollusc. Therefore investigating the purification methods of Neomysis japonica' s trypsin-like enzymes studing the physical -chemical character of its trypsin-like enzymes and other proteinases has crucial theoretic significance and applied importance.In this thesis, the histology of the digestive system and the distribution of digestive enzymes in Neomysis japonica were studied by histology and histochemistry methods. The physical-chemical character of Neomysis japonica' s extracted crude proteinases were investigated. Trypsin-like enzymes of Neomysis japonica was purified by (NH4)2S04 class-ification depositions and two different affinity chromatography, then was studied in its characters.The digestive system of Neomysis japonica is mainly composed of foregut midgut and hindgut. Midgut gland is the main digestive gland and the secretion of R-cells and B-cells found in Neomysis japonica' s midgut gland is evident.By the means of (NH4)2S04 classification depositions when the saturation of (NH4)2S04 is between 25% and 50%, and then by Benzamidine-Sephrose 4B affinity chromatography or CEOM-Sephrose 4B affinity chromatography, Neomysis japonica' s trypsin-like enzymes is attained,which has a molecular weight of 25. 7kDa by SDS-PAGE with 12% separation gel.The activity of Neomysis japonica' s extracted crude proteinases and trypsin-like enzymes is relatively higher between 25~50癈, pH6. 0(7. 0)~ 11.0, and highest at 37癈,pH 8. 0. Extracted crude proteinases and trypsin -like enzymes of Neomysis japonica can adapt to a large range variation of temperature and pH, which is the same as of Antarctic krill' s. Neomysis japonica' s trypsin-like enzymes can hydrolyse proteins more efficiently compared to bolvin trypsin' s, at 37癈,pH 8.0.It is thought that Neomysis japonica' extracted crude proteinases and trysin-like enzymes has a widely application foreground.