Abstract: Mechanism of the enzymolysis of muscle proteins from Harengula Zunasi Bleeker by compound enzyme that obtainedfrom mixture with papain and flavorease was studied. The optimum conditions of compound enzyme for enzymolysis muscle proteinare at enzyme consistency 7.5×103IU/g protein, temperature 45℃, pH6.5 and substrate consistency 5.5g protein % throughorthogonal trial with the constant time of 2 h. Under the optimum conditions, there are 3 linear relationship models expressed asDH%=0.026×[hydrolysis time]+8.85 (r=0.98), TFAA (total free amino acids of hydrolysate) =0.16×[hydrolysis time]+38.76(r=0.99) and MLPL(mean length of peptide linkage of hydrolysate)=-0.019×[hydrolysis time]+10.79(r=-0.96).The analysisof free amino acids revealed that compound enzyme has the strongest hydrolysis specificity toward the peptide linkages suppliedby cysteine and phenylalanine+tyrosine and the lowest hydrolysis specificity toward the peptide bonds supplied by tryptophane,proline, asparaginic acid, serine, glycine and glutamic acid. Meanwhile, the amino acids arriving at maximum hydrolyzing capac-ity before 210 min may have participated in the forming of the new peptide bonds at certain extent after arriving at themselvesmaximum hydrolyzing capacity. The determining of nitrogen content revealed that there is significant difference of the moleculesize of nitrogenous compositions among centrifugal hydrolysates, 0.45 μm hydrolysates and 0.22 μm hydrolysates at sametime of a range from 30 to 210 min because their nitrogen content has significant difference. The determining of molecularweight revealed that there is no significant difference in mean of relative molecular weight of all centrifugal hydrolasates and therelative molecular weight being from 300 to 1200 is covered 66% to 78% of total of the molecule number in centrifugal hydroly-sates. It is possible to give fundament and recommendations for the all-around utilization of Harengula Zunasi due to this work.

Key words: muscle protein, Harengula Zunasi bleeker, enzymolysis, compound enzyme, mechanism