Singh T K, Fox P F, Healy A
Department of Food Chemistry, University College, Cork, Irish Republic.
J Dairy Res. 1997 Aug;64(3):433-43. doi: 10.1017/s0022029997002227.
Several peptides were isolated from the diafiltration retentate, prepared using 10 kDa membranes, of the water-soluble extract from a commercial mature Cheddar cheese and identified by amino acid sequencing and mass spectrometry. Most of the peptides were from the N-terminal half of the beta-casein, but peptides from alpha s1- and alpha s2-caseins were also identified; the extract also contained alpha-lactalbumin. Identified peptides showed the important role played by lactococcal cell envelope proteinases in the degradation of primary proteolytic products from alpha s1- and beta-caseins, produced by chymosin and plasmin respectively. Plasmin seemed to be involved in the hydrolysation of alpha s2-casein. Several phosphopeptides were identified and the action of phosphatase on these peptides was evident.
从市售成熟切达干酪的水溶性提取物中，使用10 kDa膜制备的渗滤截留物中分离出几种肽，并通过氨基酸测序和质谱法进行鉴定。大多数肽来自β-酪蛋白的N端半段，但也鉴定出了来自αs1-和αs2-酪蛋白的肽；提取物中还含有α-乳白蛋白。鉴定出的肽显示了乳球菌细胞包膜蛋白酶在分别由凝乳酶和纤溶酶产生的αs1-和β-酪蛋白的初级蛋白水解产物降解中所起的重要作用。纤溶酶似乎参与了αs2-酪蛋白的水解。鉴定出了几种磷酸肽，磷酸酶对这些肽的作用很明显。
