毛霉AS3.2778脯氨酸氨肽酶的部分纯化及性质研究

毛霉蛋白酶对大豆蛋白有较高的水解效率并对蛋白水解物有良好的脱苦效果,因此在大豆多肽的制备方面显示出很好的应用前景。为了开发这一蛋白酶系,实验中P采用硫酸铵盐析、离子交换层析、疏水层析及凝胶层析等方法对其进行了分离纯化,从雅致放射毛霉AS3.2778的发酵麸曲中部分纯化得到一氨肽酶组分,并对其性质进行了探讨。纯化的毛霉氨肽酶是一典型的脯氨酸氨肽酶,它对小肽N端的脯氨酸有非常强的水解能力;该氨肽酶在40～45℃、pH6.5有最大催化活性,在30℃以内,pH5.0～8.0有很好的稳定性;在所试验的几种蛋白酶抑制剂中,仅1 mmol/L的苯甲基磺酰氟(PMSF)对毛霉氨肽酶有抑制作用,由此说明纯化的毛霉氨肽酶可能是一种丝氨酸蛋白酶;常见金属离子对该氨肽酶活性的影响不明显;脱苦实验结果表明,纯化的毛霉氨肽酶对于大豆蛋白水解物的苦味有明显的去除效果。

Partial Purification and Properties of One Prolyl-aminopeptidase from Mucor AS3.2778

Proteases from Mucor had a good application prospect in the production of soy-polypeptides for their high hydrolysis efficiency to soy protein and debittering effect to hydrolysate.To explore these proteases,this study used ammonium sulfate precipitation,ion exchange chromatography,hydrophobic chromatography and gel filtration chromatography,and investigated the properties of one aminopeptidase purified from the fermented wheat bran by Actinomucor elegans AS3.2778.The purified aminopeptidase was a particular prolyl-aminopeptidase,which had a very high hydrolysis activity to N-terminal proline of peptides.It had the maximum activity at pH6.5 40~45℃,was stable in the pH range of 5.0~8.0 at <30℃,and could be inhibited by the serine protease inhibitor,PMSF,indicated that it may belong to the serine protease family.The effect of debittering for bitter peptides among SPI hydrolysate with Alcalase was clearly found by proly-aminopeptidase treatment for 3 h.