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背景对于患有严重分解代谢疾病、肠道功能障碍或免疫缺陷综合征的患者,谷氨酰胺是一种条件必需氨基酸。谷氨酰胺是许多肠内营养制剂的天然成分,但目前还缺乏有效的研究方法,无法定量测定膳食中的谷氨酰胺含量。目的利用新开发的蛋白质/肽结合谷氨酰胺评估方法来评估经选择的肠内营养制剂中的谷氨酰胺含量。方法共研究了14种市售肠内营养制剂(10种整蛋白型制剂,4种短肽型制剂)。去除具有干扰效应的脂肪和碳水化合物,通过化学发光法测定纯化制剂内的氮含量,通过三步法评估蛋白质/肽结合谷氨酰胺;采用新型双(三氟乙酰氧基)碘苯(BTI)水解前衍生技术将谷氨酰胺转化为对酸稳定的二氨基苯甲酸(DABA)。以新型微波技术水解衍生物,然后用反相高效液相色谱(RP-H PLC)丹酰氯柱前衍生法测定氨基酸含量。结果整蛋白型肠内营养制剂内的谷氨酰胺含量介于5.2～8.1g/16g氮。短肽型制剂中测得的谷氨酰胺含量明显较低(1.3～5.6g/16g氮)。结论日常肠内营养摄入可能能满足健康人的需求,但并不能为应激状态下的患者提供足量谷氨酰胺。肠内营养制剂内的谷氨酰胺含量不能满足应激患者的需要。
Background Glutamine is a conditionally essential amino acid for patients with severe catabolic, gut dysfunction, or immunodeficiency syndrome. Glutamine is a natural component of many enteral nutrition preparations, but currently there is a lack of effective research methods to determine the amount of glutamine in the diet. Purpose The newly developed protein / peptide-bound glutamine assay was used to assess glutamine levels in selected enteral nutrition formulations. Methods A total of 14 commercial enteral nutrition preparations (10 kinds of whole protein preparations and 4 kinds of short peptide preparations) were studied. The fats and carbohydrates with interference effects were removed, the nitrogen content in purified preparations was determined by chemiluminescence and the protein / peptide-bound glutamine was evaluated by three-step method. A novel bis (trifluoroacetoxy) iodobenzene Pre-hydrolysis derivatization converts glutamine to acid-stable diaminobenzoic acid (DABA). A novel microwave technique was used to hydrolyze the derivatives, and then the amino acid content was determined by RP-H PLC with dansyl chloride precolumn derivatization. Results The content of glutamine in the whole protein enteral nutrition preparation ranged from 5.2 to 8.1g / 16g nitrogen. The glutamine content was significantly lower in the short peptide formulation (1.3-5.6 g / 16 g nitrogen). Conclusion Daily enteral nutrition intake may be able to meet the needs of healthy people, but not enough glutamine for patients under stress. Glutamine levels in enteral nutrition preparations do not meet the needs of stress patients.