Characterization of the proteases involved in gel weakening of beef heart surimi.
The goal of this study was to elucidate the nature and characteristics of the proteases involved in gel weakening of beef heart surimi. Acidic (E1) and neutral (E2) protease extracts were prepared from the surimi. The major active components in E1 were found to be cathepsins B and L. E1 exhibited optimum activity to hydrolyze substrates specific to cathepsins B and B+L at 50 degrees C and pH 5.5. At pH 6.0, it retained approximately 50% of its maximum activity. The catheptic activity of E1 was inhibited almost completely by E-64 and leupeptin. The active component in E2 was unidentified and was not inhibited by cysteine or serine protease inhibitors. However, beef plasma powder effectively inhibited the hydrolysis of FITC-casein and myosin heavy chain by E2.
Wang
B
B
Department of Animal Sciences, University of Kentucky, Lexington, Kentucky 40546, USA.
Xiong
Y L
YL
D000818:Animals; D002403:Cathepsins / Q000378:metabolism*; D002417:Cattle; D010450:Endopeptidases / Q000378:metabolism*; D005511:Food Handling; D005782:Gels; D006321:Heart; D007700:Kinetics; D008461:Meat Products; D009206:Myocardium / Q000201:enzymology*
D005782:Gels; D002403:Cathepsins; D010450:Endopeptidases