超高压对鳙鱼肌动球蛋白物化特性的影响
Effect of ultra-high pressure on the physicochemical properties of actomyosin from bighead crap (Arstichthys nobilis)
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摘要: 研究不同超高压条件（100、300、500 MPa,保压15、30、45 min）下鳙鱼肌动球蛋白物化特性的改变。结果表明,随着压力和时间的增加,鳙鱼肌动球蛋白的溶解度降低,浊度基本呈上升的趋势,表明肌动球蛋白发生了聚集变性。SDS-PAGE显示超高压引起肌动球蛋白发生交联聚集形成了大分子物质。超高压处理后鳙鱼的Ca2+-ATP酶(Ca2+-ATPase)活性消失,表明肌动球蛋白发生了变性。随着压力的增加和加压时间的延长,肌动球蛋白的表面疏水性增加,表明超高压使蛋白氨基酸的疏水性基团暴露。随着压力的增大,肌动球蛋白的总巯基含量减少,二硫键含量升高,表明肌动球蛋白中的巯基发生氧化,形成了二硫键。鳙鱼肌动球蛋白上述物化特性的改变证明超高压诱导使其构象发生了改变。Abstract: Changes of physicochemical properties in natural actomyosin from Arstichthys nobilis induced by ultra-high hydrostatic pressure ( 100, 300, 500 MPa for 15, 30, 45 min) were investigated. The results revealed that the solubility of actomyosin decreased while the turbidity increased with the increase of pressure and time, indicating the accumulation of protein aggregates and denaturation.SDS-PAGE showed that ultra-high pressure induced the cross-linking and accumulation of actomyosin to form macromolecular substances.Ca2+-ATPase activity of actomyosin treated by ultra-high pressure was lost, suggesting the denaturation of actomyosin.Surface hydrophobicity of actomyosin increased when the pressure and pressurization time increased, indicating that the exposed hydrophobic residues increased upon application of high pressure. The total sulfhydryl content of actomyosin decreased while the disulfide bond content increased with the increase of pressure, which confirmed that the sulfhydryl group of actomyosin underwent oxidation to form disulfide bonds. These variations in the physicochemical properties demonstrate that the conformation of actomyosin extracted from Arstichthys nobilis changes after ultra-high pressure processing.
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