Enzymatic properties of UFE,a novel marine fibrinolytic enzyme

A novel potent protease, Urechis unicinctus fibrinolytic enzyme （UFE）, was firstly discovered. The enzymatic properties of UFE were further investigated.As a low molecular mass protein,UFE appeared to be very stable to heat and pH.When temperature was below 50 ℃ ,the remnant enzyme activity remained almost unchanged, but when temperature was raised to 60 ℃ ,the remnant enzyme activity began to decrease rapidly. UFE was quite stable in the range of pH value from 3 to 12,especially in slightly alkaline pH value.Mn^2＋ ,Cu^2＋ and Fe^2＋ ions were activators of UFE, while Fe^3＋ and Ag^＋ ions were inhibitors of UFE.Fe^2＋ ion along with Fe^3＋ ion might regulate UFE activity in vivo. The optimum pH and temperature of UFE were about 8 and 50 ℃ ,respectively. Other characteristics of this enzyme were also studied. Systematic research results are significant when UFE is applied for medical and industrial purposes.

Changes of visceral properties and digestive enzymes in the herbivorous marine teleost Siganus canaliculatus fed on different diets

The rabbitfish Siganus canaliculatus is one of the few cultured herbivorous marine teleosts. To better understand the digestive physiology of this fish and provide data for designing formulated feed using macroalgae as an ingredient, the changes of visceral properties and digestive enzyme activities were investigated after the juveniles were fed on different types of food including raw fish（RF）, formulated diet（FD） or macroalgae Enteromorpha prolifra（EP） and Gracilaria lemaneiformis（GL） for eight weeks. The results showed that the hepatosomatic and viscerosomatic indices in the RF and FD groups, as well as the relative intestine length（RIL） in the EP and GL groups, were significantly higher than those in other groups. Additionally, differences in the histological structure of the liver and anterior intestine were also observed among different dietary groups. The hepatic nuclei were displaced to the periphery by lipid inclusions in fish fed RF. The highest levels of mucosal folds were found in the anterior intestines of fish fed macroalgae. Digestive enzyme activity profiles showed obvious fluctuations in the first three weeks, and then leveled off in the following weeks. The levels of protease, lipase and α-amylase in the alimentary tract showed changes related to the levels of dietary protein, lipid and carbohydrate, respectively.Although macroalgae significantly inhibited the activity of protease in the stomach, it increased RIL and the number of mucosal folds in the anterior intestine so as to compensate for the influences on protease activities in the stomach. This study suggests that the digestive tract of rabbitfish can well adapt to different diets, and needs about three weeks to physiologically acclimatize to the nutritional status, thus implying that rabbitfish are somewhat omnivorous.

Evaluation of the chemical constituents,antioxidant and enzyme inhibitory activities of six Yemeni green coffee beans varieties

Coffee arabica L.is an economical crop cultivated in many countries including Yemen.The present study evaluated the phytochemical contents of the methanolic extracts,prepared by maceration,of six Yemeni green coffee beans varieties namely Esmaeli,Hamadi,Harazi,Mattari,Odaini and Yafei.Antioxidant(phosphomolybdenum,antiradical,reducing power and ferrous chelating),and enzyme inhibition activity of the extracts against acetylcholinesterase butyrylcholinesterase,tyrosinase,α-glucosidase,andα-amylase were also studied.Quantification of total phenols revealed that all green beans varieties were richer in their total polyphenolic(63.77-110.98 mg gallic acid equivalent per g of extract)content than their flavonoids one(2.86-5.57 mg rutin equivalent per g of extract).HPLC-MS/MS analysis of 30 selected bioactive compounds showed that all varieties had the same types of phytoconstituents with differences in their relative abundance.Caffeine(1613.89-2466.38μg/g)followed by 5-caffeoylquinic acid(1017.63-1313.39μg/g)were the dominant compounds in all varieties with caffeine more abundant in Esmaeli variety while 5-caffeoylquinic acid in Odaini variety.All varieties displayed a pronounced antioxidant property in all the in vitro assays with Odaini variety significantly(p<0.05)exerted the highest anti-DPPH radicals(253.96 mg Trolox equivalent(TE)/g),metal chelating(19.73 mg Disodium edetate equivalents/g),Cu^(2+)(441.11 mg TE/g)and Fe3+(221.04 mg TE/g)reducing activities.Furthermore,the majority of green coffee beans varieties showed comparable enzyme inhibition property with highest activity recorded against tyrosinase(39.35-46.96 mg kojic acid equivalents/g)and acetylcholinesterase(1.80-2.17 mg galanthamine equivalents/g)enzymes.In conclusion,all Yemeni green coffee beans varieties have proven to be rich source of biochemicals with beneficial impact on human health and could be of significant applications in food,pharmaceutical and cosmetics industry.