Pollak A, Schober E, Coradello H, Lischka A, Levin S, Waldhauser F, Lubec G
Acta Diabetol Lat. 1984 Apr-Jun;21(2):123-31. doi: 10.1007/BF02591101.
It has been suggested previously that non-enzymatic glycosylation of certain enzymes results in decreased enzymatic activity. In order to examine the role of high blood glucose concentrations (BG) on serum alkaline phosphatase (AP) activity, we determined BG and serum AP in 32 healthy children during an oral glucose tolerance test (OGTT) and in 10 type I diabetic children at 30-min intervals for at least 150 min. A significant negative correlation was noted for BG and AP during the oral glucose load (r = -0.57, p less than 0.01). In diabetics, however, only children with marked BG fluctuations showed this inverse relationship between BG and AP. These observations could be explained by the formation of a Schiff base as the initial step of non-enzymatic glycosylation of AP. This assumption was further confirmed by in vitro experiments, in which AP was incubated with glucose resulting in decreased enzymatic activity. The dialyzable aldimine formed initially is subsequently stabilized as ketoamine after long-term incubation.
先前有人提出，某些酶的非酶糖基化会导致酶活性降低。为了研究高血糖浓度（BG）对血清碱性磷酸酶（AP）活性的作用，我们在口服葡萄糖耐量试验（OGTT）期间测定了32名健康儿童以及10名I型糖尿病儿童的BG和血清AP，间隔30分钟至少测定150分钟。口服葡萄糖负荷期间，BG与AP呈显著负相关（r = -0.57，p < 0.01）。然而，在糖尿病患者中，只有BG波动明显的儿童才表现出BG与AP之间的这种反比关系。这些观察结果可以用席夫碱的形成来解释，这是AP非酶糖基化的第一步。体外实验进一步证实了这一假设，在该实验中，AP与葡萄糖一起孵育导致酶活性降低。最初形成的可透析醛亚胺在长期孵育后随后稳定为酮胺。
