| The extraction, separation, purification and antibacterial characterstics of antibacterial protamie from adult carp spermary that is the commonly used fresh water breed acqatics and processing objects in China were studied systematically. At the same time the antibacterial mechanism for the protamine was researched. The results offered a theoretical base for the development and utilization of carp spermary as a kind of natural food preservative of antibacterial protamine.The main research results are below.Antibacterial protamine from the spermary of different carp breeds at the same autumn had no significant effect on recovery rate and antibacterial activity, while the antibacterial protamine form the spermary at different autumns of the same breed showed significant effects on the extraction rate and antibacterial activity (p<0.05), and the phase V was the highest (4.63 % and 84.5 %, respectively).Based on the results of optimizing study on the H2SO4 concentration, extracting temperature, extracting time, and the selection of protein precipitator for higher extraction rate and antibacterial activity,a better extracting and separating condition was gained: using 4 mL H2SO4 of 7.5 % at 10℃ to extract per g spermary for 2 hours, then separating antibacterial protamine with 95 % cool ethanol (H2SO4 ethanol is 1:3 (V/V)).In this experiment, ultrasonic technique was used to extract for the first time. The results showed that 1.0 A ultrasonic can shorten the extracting time greatly from 2 hours to 20 minutes,decrease the extracting reactant concentration from 7.5% to 5% and increase the extraction rate of of antibacterial protamine.In this experiment, the minimal inhibition concentration (MIC) and antibiotic spectrum of carp antibacterial protamine was studied for the first time with some common food- spoiling microorganisms, the effects of pH value, temperature, metal ion, protease on protamine antibacterial activity were also investigated. The results showed that the antibacterial activity was better at neutral and basic pH value (pH 7-9); the protamine had a good endurance to temperature; the metal ions could affect the antibacterial activity of protamine, the higher ion concentration, the lower activity. And the effects of Al3+, Fe3+ on activity were higher than Ca2+,Mg2+, but the effects of Ca2+, Mg2+ on activity were higher than K+, Na+. a-rennet could decrease half ofprotamine activity, and trypsin, papsin could induce most of antibacterial activity to loss, but pepsin could make the antibacterial activity whole loss. And also found that glycin and sodium acetic compounds or cooperated with EDTA could improve the antibacterial activity greatly.Isoelectric settlemental separation, sephadex G-50 gel filtration chromatography, CM Sepharose CL-6B ion exchange chromatography were employed to purificate .separate the antibacterial protamine and a basic protein with high antibacterial activity was gained. The basic protein showes a single active peat in RP-HPLC detection and a SDS-PAGE band, and its molecular weight was 15320 daltons (D). It contained higher alkalinity amino acid and was a triprotamine, the total amount of lysine, histidine and arginie was 40.67 %, and the lysine content was 22.85%. The isoelectric point (pI) of the protein was over 10 after detecting with PAGE isoelectric focusing electrophoresis.After investigating the effects of antibacterial activity on the growth of Bacillus subtilis, we found that protamine could inhibit the growth of Bacillus subtilis. Electron microscope and microscopy images showed that protamine did not destroy the cellular wall. Also the effect of protamine on succinate dehydrogenase (SDH) and malata dehydrogenase (MDH) in cells of Aspergillus niger was detected. The results showed: protamine could significantly inhibit the activities of succinate dehydrogenase and malata dehydrogenase. And the plausible antibacterial mechanism was that the components of protamine could combine with the branching chains of these two enzymes, which changed the structures of the en...
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