Berghen P, Dorny P, Vercruysse J
Am J Vet Res. 1987 Apr;48(4):664-9.
Blood pepsinogen concentrations in cattle were determined, using a simple, direct method based on the hydrolysing effect of serum on buffered bovine albumin substrate (2 g/dl). The amount of tyrosine released was measured at 680 nm, using the Folin and Ciocalteu's colorimetric method. To ensure an optimal digestion in vitro, a glycine-hydrochloric acid buffer (0.1M) was evaluated at various pH. Serum samples with medium (2,591 mU of tyrosine) and high (6,222 mU of tyrosine) pepsinogen concentrations had the highest proteolytic activity at pH 2.5. Substituting albumin by hemoglobin substrate resulted in almost double the amount of hydrolyzed products. For preparation of standard pepsin or pepsinogen curves, the incorporation of serum (activated or inactivated) diminished the tyrosine released to only half the amount obtained without serum. The use of serum or plasma did not significantly affect the results of the test, nor did prolonged storage at -70 C result in marked differences in the results.
采用基于血清对缓冲牛白蛋白底物（2 g/dl）水解作用的简单直接方法，测定了牛的血胃蛋白酶原浓度。使用福林和乔卡泰乌比色法在680 nm处测量释放的酪氨酸量。为确保体外最佳消化，在不同pH值下评估了甘氨酸 - 盐酸缓冲液（0.1M）。胃蛋白酶原浓度中等（2591 mU酪氨酸）和高（6222 mU酪氨酸）的血清样品在pH 2.5时具有最高的蛋白水解活性。用血红蛋白底物替代白蛋白导致水解产物量几乎翻倍。为制备标准胃蛋白酶或胃蛋白酶原曲线，加入血清（活化或灭活）使释放的酪氨酸减少到无血清时获得量的一半。使用血清或血浆对测试结果没有显著影响，在 -70°C下长时间储存也未导致结果有明显差异。
