Pathways of formation of glycoxidation products during glycation of collagen.
Pathways of formation of glycoxidation products during glycation of collagen.
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胶原蛋白糖化过程中糖氧化产物的形成途径。
DOI：
10.1021/bi00046a020
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发表时间：
1995
期刊：
影响因子：
2.9
通讯作者：
Baynes,JW
中科院分区：
文献类型：
--
作者：
Wells-Knecht,MC;Thorpe,SR;Baynes,JW
修订稿于 1995 年 9 月 28 日收到®摘要：糖氧化产物 (GOP)，如 /V6-(羧甲基) 赖氨酸 (CML) 和戊糖苷，是在体外氧化条件下葡萄糖与蛋白质反应形成的。目前还不确定这些 GOP 是源自蛋白质上阿马多里加合物的氧化，还是源自葡萄糖或阿马多里重排之前形成的中间体的氧化。为了解决这个问题，我们在抗氧化条件下将胶原蛋白与 200 mM 磷酸盐缓冲液（pH 7.4）中的 250 mM 葡萄糖反应，产生富含 Amadori 加合物的蛋白质，但仅含有微量 GOP。然后将这种“预糖化”胶原蛋白在氧化条件下暴露于[13Ce]葡萄糖，产生天然的和[13C2]-CML。在 200 mM 磷酸盐缓冲液中，[13C2]-CML 是主要产物，即使在低 (5 mM) pCej 葡萄糖浓度下也是如此，这表明 Amadori 化合物在高磷酸盐中形成 CML 中的作用有限。天然和[13C2]-CML 的相对产量随磷酸盐浓度的变化而变化，在更生理性的（10 mM）磷酸盐下变得相似。我们得出的结论是，在体外高磷酸盐浓度下蛋白质糖化过程中，GOP 主要是通过氧化游离葡萄糖或阿马多里重排之前快速形成的中间体（例如甲醇胺或席夫碱加合物）而形成的。相反，在体内磷酸盐和葡萄糖浓度较低的情况下，Amadori 加合物可能是更重要的 GOP 前体。在开发抑制糖尿病美拉德反应的治疗方法时必须考虑糖氧化反应通过多种途径进行的事实。
Revised Manuscript Received September 28, 1995® abstract: Glycoxidation products (GOPs), such as/V6-(carboxymethyl) lysine (CML) and pentosidine, are formed during reaction of glucose with protein under oxidative conditions in vitro. It is uncertain whether these GOPs are derived from oxidation of Amadori adducts on protein or from oxidation of glucose or intermediates formedprior to the Amadori rearrangement. To address this question, we reacted collagen with 250 mM glucose in 200 mM phosphate buffer, pH 7.4, under antioxidative conditions, yielding a protein rich in Amadori adducts, but with only traces of GOPs. This “preglycated” collagen was then exposed to [l3Ce] glucose under oxidative conditions, producing both naturaland [13C2]-CML. At 200 mM phosphate buffer,[13C2]-CML was the major product, even at low (5 mM) pCejglucose concentration, indicating a limited role for Amadori compounds in formation of CML in high phosphate. The relative yields of natural and [13C2]-CML variedwith phosphate concentration, becoming similar at more physiological (10 mM) phosphate. We conclude that duringglycation of proteins at high phosphate concentrations in vitro, GOPs are formed primarily by oxidation of free glucose or rapidly-formed intermediates preceding the Amadori rearrangement, such as carbinolamine or Schiff base adducts. In contrast, at lower phosphate and glucose concentrations in vivo, the Amadori adduct may be the more significant precursor of GOPs. The fact that glycoxidation reactions proceed by multiple routes must be considered in the development of therapeutic approaches for inhibiting the Maillard reaction in diabetes.