Lipovac V, Gavella M, Sverko V
Vuk Vrhovac University Clinic for Diabetes, Endocrinology and Metabolic Diseases, Medical Faculty, University of Zagreb, Croatia.
Acta Diabetol. 1994 Sep;31(3):156-9. doi: 10.1007/BF00570371.
The aims of this study were to determine whether in vitro nonenzymatic glycation of proteins by sialic acid (sialylation) induces the generation of fluorescence, and whether the presence of this keto sugar may affect the generation of fluorescence induced by other sugars. Incubation of bovine serum albumin (BSA; 1.5 mM) with sugars (50 mM in 0.2 M phosphate buffer, pH 7.4, at 37 degrees C) resulted in a time-dependent increase of formaldehyde release (moles/moles of protein). On the 17th day of incubation, the value was 0.53 +/- 0.06, 0.78 +/- 0.15 and 1.23 +/- 0.18 for sialic acid, fructose and glucose respectively, compared with 0.37 +/- 0.05 for BSA. The fluorescence intensity (arbitrary units/mg protein) was higher after 17 days of incubation with fructose (16.9 +/- 1.8) than with glucose (12.7 +/- 1.3), while no significant increase was noted with sialic acid compared with BSA (3.8 +/- 0.4). Fluorescence intensity increase by incubation with glucose (50 mM) was significantly reduced by sialic acid (20 mM) after both 10 (P < 0.001) and 14 (P < 0.001) days of incubation, while inhibition was weaker after 14 (P < 0.05) than after 10 (P < 0.001) days when fructose (50 mM) was used as the glycating agent. This indicates that sialic acid can be potentially used to limit the damage from adverse glycation-induced processes.
本研究的目的是确定唾液酸对蛋白质的体外非酶糖基化作用（唾液酸化）是否会诱导荧光产生，以及这种酮糖的存在是否会影响其他糖类诱导的荧光产生。将牛血清白蛋白（BSA；1.5 mM）与糖类（在0.2 M磷酸盐缓冲液中50 mM，pH 7.4，37℃）孵育，导致甲醛释放量（每摩尔蛋白质的摩尔数）随时间增加。在孵育第17天时，唾液酸、果糖和葡萄糖的该值分别为0.53±0.06、0.78±0.15和1.23±0.18，而BSA为0.37±0.05。与果糖孵育17天后的荧光强度（任意单位/毫克蛋白质）（16.9±1.8）高于与葡萄糖孵育后的（12.7±1.3），而与BSA（3.8±0.4）相比，唾液酸处理后荧光强度无显著增加。在孵育10天（P<0.001）和14天（P<0.001）后，20 mM唾液酸均显著降低了与50 mM葡萄糖孵育后的荧光强度增加，而当使用50 mM果糖作为糖基化剂时，14天（P<0.05）后的抑制作用比10天（P<0.001）后的弱。这表明唾液酸可能可用于限制有害糖基化诱导过程造成的损害。
