Fractionation and Characterization of Protease Inhibitors from Fish Eggs Based on Protein Solubility

Abstract

A protease inhibitor was fractionated from fish eggs using methods based on protein solubility. Fractionation efficiency was evaluated with regard to percent recovery and total inhibitory activity (U). The fractionation of protease inhibitor (PI) from egg extracts of skipjack tuna (ST, Katsuwonus pelamis), yellowfin tuna (YT, Thunnus albacores), and Alaska pollock (AP, Theragra chalcogramma) was performed by precipitation with cold acetone or ammonium sulfate (AS). Fractions exhibiting the strongest inhibitory activity contained 20-40% (v/v) cold acetone or 40-60% saturated AS fractions. AS fractionation was more effective in isolating PI than was precipitation with acetone. The total inhibitory activity and percent recovery of fraction obtained with AS 40-60% toward trypsin and Nα-benzoyl-Larginine-p-nitroanilide (BAPNA) were 4,976 U and 24.2% for ST, 3,331 U and 38.1% for YT, and 4,750 U and 43.8% for AP, respectively. In comparisons against six commercial proteases, 40-80% AS fractions, made by combining the 40-60% and 60-80% AS fractions from fish egg extract, exhibited the strongest inhibition of trypsin when using a casein substrate. These results suggest that fish eggs act as serine protease inhibitors and may be useful for protease inhibition in foodstuffs.

Preparation and characterization of protein isolate from Yellowfin tuna Thunnus albacares roe by isoelectric solubilization/precipitation process

“…And yellowfin tuna roe, a byproduct generated from fish processing (1.5-3.0 % of total weight), is generally used as animal feed or pet food preparation (Chalamaiah et al 2013;Klomklao et al 2013;Intarasirisawat et al 2011). In our previous study, we fractionated inhibitors from fish roes, and confirmed the distribution of protease inhibitory activity in crude extracts from fish roes (Ji et al 2011;Kim et al 2013a;2013b). In the present study, yellowfin tuna roe was used as a model for fish processing byproduct, and it was the starting material for isoelctric solubilization/precipitation (ISP).…”

Food functionalities and bioactivities of protein isolates recovered from skipjack tuna roe by isoelectric solubilization and precipitation

“…The underutilized skipjack tuna roe (STR) requires processing methods for conversion to more marketable and acceptable forms, such as protein concentrates, isolates, and extracts. Previous studies characterized the ingredients, chemical composition (Heu et al, ; Lee, Lee, et al, ), fractions, and characteristics of the protease inhibitors (Kim et al, ), concentrates (Park et al, ; Yoon, Lee, et al, ), and protein isolates (Lee, Park, et al, ) in fish roes.…”

Chromatographic Fractionation of Protease Inhibitors from Fish Eggs

“…8 protease inhibitor (Ji et al, 2011), protease inhibitor (Kim et al, 2013 Target proteases, 기질 및 buffer crude extracts (CE) protease inhibitor sephadex G-50 gel matrix DEAE-sepharose CL-6B anion exchange resin, target protease serine protease trypsin BAPNA (N -benzoyl-L-arginine-p-nitroanilide) SigmaAldrich Co. (St. Louis, MO, USA) , . 0.1 M Tris-HCl buffer (pH 9.0) Dawson et al (1986) .…”