THE MAILLARD REACTION BETWEEN RIBOSE 5-PHOSPHATE AND CELLULAR AMINES

5-磷酸核糖与细胞胺之间的美拉德反应

• 批准号: 7381427
• 负责人: ROGER K SANDWICK
• 金额: $ 8.11万
• 依托单位: UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7381427
• 关键词: MAILLARD; REACTION; BETWEEN; RIBOSE; PHOSPHATE

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The Maillard reaction between sugars and amines is a principal contributor to the colors, flavors, and aromas generated in baked/fried foods and to the production of advanced glycation end-products (AGEs) in physiological systems. Ribose 5-phosphate (R5P), a component of the pentose phosphate pathway in cells, has been shown to undergo the Maillard browning reaction with simple amines at rates approximately 100 times faster than most other common sugars and sugar phosphates. The potential of significant R5P glycation of cellular amines and proteins is, however, currently poorly understood. The goal of the project was to fully characterize kinetics and reaction mechanisms of the reaction of R5P with amines with particular attention towards the effect of the reaction on protein cross-linking and function. R5P (50 mM) was shown to react rapidly with simple amines/amino acids and target proteins (lysozyme, lactalbumin, ribonuclease A, histones, myoglobin) at 37 C with initial interactions noted generally within hours and browning reactions obvious generally within a day. Native gel and isoelectric focusing electrophoretic patterns suggest a rapid replacement of basic amine side chains (lysines and arginines) with negatively charged R5P groups. Modeling of the R5P/protein system vs. a simple R5P/N-acetyl lysine system illustrates an enhanced rate for the reaction with proteins. R5P was eventually removed from solution despite a greater than ten-fold molar excess over total protein amine levels, thus indicating a repeated R5P-degrading reaction coupled with subsequent regeneration of the initial amine group. 31P nuclear magnetic resonance (NMR) spectroscopy analysis of microfiltrated samples of the reaction revealed phosphate loss from the R5P nucleus with time. Protein ¿ protein cross-linking was remarkably fast with dimers being seen within 4 h for systems with highly basic proteins (i.e. histones) and within four days for more neutral proteins. The implications of this investigation strengthen a proposal that R5P could be a significant source of advanced glycation end-products (AGEs) in cellular conditions.

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。糖和胺之间的美拉德反应是烘焙/油炸食品中产生的颜色、风味和香味以及生理系统中晚期糖基化终产物（AGEs）产生的主要贡献者。核糖5-磷酸（R5 P）是细胞中戊糖磷酸途径的一种组分，已显示与简单胺进行美拉德布朗宁反应的速率比大多数其他常见糖和糖磷酸盐快约100倍。然而，目前对细胞胺和蛋白质的显著R5 P糖化的潜力知之甚少。该项目的目标是充分表征R5 P与胺反应的动力学和反应机制，特别关注反应对蛋白质交联和功能的影响。R5 P（50 mM）显示在37 ℃下与简单的胺/氨基酸和靶蛋白（溶菌酶、乳白蛋白、核糖核酸酶A、组蛋白、肌红蛋白）快速反应，通常在数小时内注意到初始相互作用，通常在一天内明显地发生布朗宁反应。天然凝胶和等电聚焦电泳模式表明，带负电荷的R5 P基团的碱性胺侧链（赖氨酸和赖氨酸）的快速更换。R5 P/蛋白质系统与简单的R5 P/N-乙酰基赖氨酸系统的建模说明了与蛋白质反应的速率提高。R5 P最终从溶液中除去，尽管超过总蛋白胺水平的摩尔过量大于10倍，因此表明重复的R5 P降解反应与随后的初始胺基的再生偶联。反应的微滤样品的31 P核磁共振（NMR）光谱分析显示磷酸盐随时间从R5 P核损失。蛋白质蛋白质交联非常快，对于具有高碱性蛋白质（即组蛋白）的系统，在4小时内观察到二聚体，对于更中性的蛋白质，在4天内观察到二聚体。这项调查的影响加强了一个建议，R5 P可能是一个重要的来源，晚期糖基化终产物（AGEs）在细胞条件。