Ekstrand B, Larsson-Raźnikiewicz M, Perlmann C
Biochim Biophys Acta. 1980 Jul 3;630(3):361-6. doi: 10.1016/0304-4165(80)90284-6.
Chymosin (EC 3.4.23.4) and rennet, the latter containing about 85% chymosin and 15% pepsin, have been compared according to their coagulation properties with native micelles of different sizes or monomeric caseins as substrate. The casein micelles were separated on columns of controlled-pore glass (CPG-10/3000), which fractionates particles of up to 300 nm diameter. The results show that the coagulation time varies with the micelle size. The effect, which is more pronounced with chymosin than with rennet, appears to be related to the availability of kappa-casein. Therefore the largest micelles, with a lower kappa-casein content, showed longer coagulation times than medium size micelles. In the region of the smallest micelles this time increases again, probably due to an increased beta-casein content. Addition of monomeric kappa-casein decreased the coagulation time with both rennet and chymosin, but alpha s1-and beta-casein had the opposite effect. When isolated monomeric caseins were treated alone with rennet or chymosin, kappa-casein caused turbidity, but alpha s1-and beta-casein did not. Centrifugation experiments with micelles after monomeric casein addition showed that a limited amount of the added casein was able to join the micelle. This was confirmed by chromatographic studies.
已根据凝乳酶（EC 3.4.23.4）和粗制凝乳酶（后者含有约85%的凝乳酶和15%的胃蛋白酶）以不同大小的天然胶束或单体酪蛋白为底物的凝血特性进行了比较。酪蛋白胶束在可控孔径玻璃柱（CPG - 10/3000）上进行分离，该柱子可分离直径达300 nm的颗粒。结果表明，凝血时间随胶束大小而变化。这种效应在凝乳酶中比在粗制凝乳酶中更明显，似乎与κ-酪蛋白的可用性有关。因此，κ-酪蛋白含量较低的最大胶束比中等大小的胶束凝血时间更长。在最小胶束区域，这个时间再次增加，可能是由于β-酪蛋白含量增加。添加单体κ-酪蛋白可缩短粗制凝乳酶和凝乳酶的凝血时间，但αs1-酪蛋白和β-酪蛋白则有相反的效果。当单独用粗制凝乳酶或凝乳酶处理分离出的单体酪蛋白时，κ-酪蛋白会导致浑浊，但αs1-酪蛋白和β-酪蛋白则不会。添加单体酪蛋白后对胶束进行离心实验表明，添加的酪蛋白中有有限量能够加入胶束。色谱研究证实了这一点。
