Kaartinen L, Salonen E M, Vaheri A, Sandholm M
Acta Vet Scand. 1988;29(3-4):485-91. doi: 10.1186/BF03548646.
Milk and whey samples from healthy and inflamed udder quarters of 10 Ayrshire cows were analyzed for proteolytic activity using radial caseolysis procedures, a fluorogenic coumaryl peptide substrate, and casein agarose zymography. Free lysosomal enzyme activity (N–acetyl–beta–D–glucosaminidase) was used as the criterion for inflammation. All mastitic milk samples had proteolytic activity, tentatively identified as plasmin (comigration at M 83 000 and characteristic fragmentation). The plasmin activities in mastitic milk were on average 2.9 μg/ml (range 0.5–12.5) as measured by radial caseolysis. Milk or whey specimens from healthy quarters were all negative except 1 in which an activity of 0.1 μg/ml was found in both specimens. The caseolytic activities were totally inhibited by 50 KITJ/ml of aprotinin, a serine proteinase inhibitor from bovine lung. No free plasminogen activator (PA) activity was found in any of the samples. Howewer, according to zymographic analyses PA molecules corresponding to urokinase were found in healthy and especially in mastitic specimens. Analysis of plasmin may provide an alternative means of screening for mastitic milk samples.
采用放射状酪蛋白分解法、荧光香豆基肽底物法和酪蛋白琼脂糖酶谱法，对10头 Ayrshire 奶牛健康和发炎乳腺区的牛奶和乳清样本进行蛋白水解活性分析。以游离溶酶体酶活性（N - 乙酰 - β - D - 氨基葡萄糖苷酶）作为炎症的指标。所有患乳房炎的牛奶样本均具有蛋白水解活性，初步鉴定为纤溶酶（在 M 83 000 处共迁移且具有特征性片段化）。通过放射状酪蛋白分解法测定，患乳房炎牛奶中的纤溶酶活性平均为2.9 μg/ml（范围为0.5 - 12.5）。健康乳腺区的牛奶或乳清样本除1份在两个样本中均检测到0.1 μg/ml的活性外，其余均为阴性。50 KITJ/ml的抑肽酶（一种来自牛肺的丝氨酸蛋白酶抑制剂）可完全抑制酪蛋白分解活性。在任何样本中均未检测到游离纤溶酶原激活剂（PA）活性。然而，根据酶谱分析，在健康样本尤其是患乳房炎的样本中发现了与尿激酶相对应的PA分子。纤溶酶分析可能为筛选患乳房炎的牛奶样本提供一种替代方法。
