Bovine placental protease specificity toward muscle connective tissue proteins
| Autor: | K. W. Miller, A L Phillips, Richard J. McCormick, W. J. Means, N. Kalchayanand |
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| Rok vydání: | 2000 |
| Předmět: |
Meat
Food Handling Placenta Connective tissue Biology Protein degradation Substrate Specificity Casein Culture Techniques Endopeptidases Genetics medicine Gelatinase Animals Zymography chemistry.chemical_classification Proteins General Medicine Consumer Behavior Molecular Weight Enzyme medicine.anatomical_structure chemistry Biochemistry Connective tissue metabolism Connective Tissue Collagenase Gelatin Animal Science and Zoology Cattle Electrophoresis Polyacrylamide Gel Collagen Food Science medicine.drug |
| Zdroj: | Journal of animal science. 78(7) |
| ISSN: | 0021-8812 |
| Popis: | Enzymes currently used to tenderize meat are not substrate-specific, resulting in extensive myofibrillar protein degradation that often produces an undesirable texture. Bovine placental metalloproteases, which selectively hydrolyze connective tissue proteins while leaving myofibrillar proteins intact, may tenderize meat without causing texture problems. Therefore, our objective was to extract and crudely purify bovine metalloproteases from bovine placenta for possible use as tenderizers in meat systems. Enzymes were extracted from homogenized tissue and purified by ammonium sulfate precipitation. Samples were collected before (crude enzyme) and after gel filtration on a Sephadex G-100 column. Spectrophotometric analysis identified one major peak (filtered enzyme). Gelatin, casein, and type I acid-soluble collagen zymography were used to determine substrate specificity. Beef myofibrillar proteins were incubated with crude and filtered enzyme fractions, enzymes quenched, and substrate degradation visualized using SDS-PAGE. Active gelatinases and collagenases exhibiting molecular weights of 57 to 65 kDa were detected on zymograms. Banding patterns from crude enzyme indicated two enzymes with both gelatinase and collagenase activity and a third enzyme with gelatinase activity only. Banding patterns from filtered enzyme indicated two enzymes with both gelatinase and collagenase activity. Proteolytic activity was not detected with casein, actin, or myosin heavy-chain substrates. Due to specificity for collagen and gelatin, these enzymes may be capable of improving the tenderness of certain cuts relatively high in connective tissue, while avoiding myofibrillar protein hydrolysis. |
| Databáze: | OpenAIRE |
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