• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.183-186
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• 2004

Various myoglobin derivatives were manufactured in pork and beef ribeye in the laboratory and their colorimetric values were measured with a chromameter. The average values of L＊ and a＊ of pork pigments were higher and b＊ values were lower than those of beef pigments. Oxymyoglobin (bright red) is considered to be a desirable fresh red meat pigment for consumer acceptance. The means of L＊, a＊ and b＊ values of oxymyoglobin were 36.41, 27.32 and 4.71 for pork and 30.54, 25.58 and 9.81 for beef, respectively. Nitrosyl hemochrome, the pigment of processed meat products like sausages and hams had L＊, a＊ and b＊ values of 47.93, 26.85 and 6.63 for pork and 41.82, 23.19 and 11.82 for beef. It was found that as a discoloration developed in meat and the meat color turned to brown, the L＊, b＊ values increased and the a＊ value decreased.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1917-1923
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• 2004

Although the proteolytic activity of the Cu(II) complex of cyclen (Cyc) is greatly enhanced upon attachment to a cross-linked polystyrene (PS), the Cu(II)Cyc-containing PS derivatives reported previously hydrolyzed only a very limited number of proteins. The PS-based artificial metalloproteases can overcome thermal, mechanical, and chemical instabilities of natural proteases, but the narrow substrate selectivity of the artificial metalloproteases limits their industrial application. In the present study, artificial metalloproteases exhibiting broad substrate selectivity were synthesized by attaching Cu(II)Cyc to a PS derivative using linkers with various structures in an attempt to facilitate the interaction of various protein substrates with the PS surface. The new artificial metalloproteases hydrolyzed all of the four protein substrates (albumin, myoglobin, ${\gamma}$-globulin, and lysozyme) examined, manifesting $k_{cat}/K_m$ values of 28-1500 $h_{-1}M_{-1}$ at 50 $^{\circ}C$. The improvement in substrate selectivity is attributed to steric and/or polar interaction between the bound protein and the PS surface as well as the hydrophobicity of the microenvironment of the catalytic centers.