Purification, Enzymology Properties And Structure Analysis Of AMP Deaminase From Pig Muscle Tissue

An AMPD was purified from fresh pork by following procedures:Cellulosephosphate chromatography,Q-Sepharose Fast Flow chromatography and5’-AMPSepharose chromatography. The preparation was formed a single band onSDS-PAGE.The purification multiple was133.68,and the specific activity2.5U/mg.The molecular weight of AMP deaminase determined with gel filtrationwas178kDa and its subunit weight determined with SDS-PAGE was87kDa.Isoelectric focusing study showed that pI value of the enzyme was6.81.Thisenzyme catalysis AMPD optimal pH of ammonia reaction for5.9,pH in the range of5.7~6.3stability.The optimum temperature is37℃,higher than42℃is not stable.AMP deaminase from different sources its basically the same activator andinhibitor. Results of the amino acid composition analysis showed that Alanine,lysine, glutamic acid, leucine proportion is higher. Use of Lasergene proteanAMPD protein secondary structure of the software analysis, obtain the Alpha helixlevel structure, Beta fold, Turn Angle, spiral Coil curl, hydrophilic and surfaceantigen division, it can be seen that the secondary structure of Alpha helixaccounted for larger proportion, and the strong hydrophilic.Changes of inosine-5’-monophosphate (IMP) contents in longissimus dorsi at4℃were analyzed by HPLC, to understand the changes of inosine-5’-monophosphate (IMP) after the pig is butchered. The result showed that storagetime affected the concentration of IMP,concentration of IMP increased untilreaching maximum on the next day, then decreased gradually. Therefore, the freshdegree of pork could be forecasted by determining the change of IMP, and it wasone of the major quality variables during storage and process.