Stability of beta_2-microglobulin in urine

尿液中β_2-微球蛋白的稳定性

• 批准号: 04671439
• 负责人: ITOH Yoshihisa
• 金额: $ 1.02万
• 依托单位: Jichi Medical School
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04671439/
• 关键词: beta_2-microglobulin; Urine; Stability; NAG-B; alpha_1-microglobulin; β2-ミクログロブリン; α1-マイクログロブリン; beta2-ミクログロブリン; 慢性腎不全; alpha1-ミクログロブリン; ブロテアーゼ; 尿中安定性; pH

Urinary beta2-microglobulin (beta2-m) is quite unstable under acid conditions. The present study was undertaken to investigate the mechanisms of this instability in order to seek suitable sampling and preservation conditions.1)beta2-m is most unstable of all 7 urinary proteins investigated : Common features of the proteins examined was that 1)all degraded at pH4.0 although alpha1-microglobulun relatively kept its antigenicity, 2)degradation was temperature dependent. However, beta2-m degradated markedly even at pH5.0. which contrasted other proteins. Sugar side chain is not an essential factor to determine the stability of proteins, but its own structure since non-glycoprotein, called protein 1, was quite stable as other glycoproteins.Proteins in normal urine was unstable than those in pathologic urine. This may be explained by the decreased activity of proteases in urine which became similar to that in serum.2)Fractionation of pathologic urine by chromatographies revealed that acid proteases are present in ConA-through fractions. Further studies are under way.3)Development of an NAG-B isoenzyme immunoassays : NAG-B was purified from human placenta and its monoclonal antibody was thus prepared. Using this assay, the reference range was thus determined in normal urine. We discovered that NAG-B was rich in seminal plasma that can limit the clinical significance of this protein as a renal tubular marker.4)Establishment of urinary alpha1-microglobulin assay : This protein proved to be most stable in urine.

尿β 2-微球蛋白（β 2-m）在酸性条件下非常不稳定。本研究旨在探讨这种不稳定性的机制，以寻求合适的采样和保存条件。1）β 2-m是所有7种尿蛋白中最不稳定的：检测的蛋白质的共同特征是：1）所有降解在pH 4. 0，虽然α 1-微球蛋白相对保持其抗原性，2）降解是温度依赖性的。然而，即使在pH 5.0下，β 2-m也显著降解。与其他蛋白质形成对比。糖侧链并不是决定蛋白质稳定性的关键因素，而决定蛋白质稳定性的主要因素是糖侧链本身的结构，因为非糖蛋白（称为蛋白1）与其他糖蛋白一样稳定，正常尿中的蛋白质比病理尿中的蛋白质更不稳定。这可能是由于尿液中蛋白酶活性降低，变得与血清中的蛋白酶活性相似。2）通过色谱法对病理尿液进行分级，发现酸性蛋白酶存在于ConA-通过级分中。3）NAG-B同工酶免疫检测方法的建立：从人胎盘组织中纯化NAG-B，制备其单克隆抗体。使用该测定法，在正常尿液中测定参考范围。我们发现NAG-B在精浆中含量丰富，这可能限制该蛋白作为肾小管标记物的临床意义。4）建立尿α 1-微球蛋白测定法：该蛋白在尿液中被证明是最稳定的。

项目成果

伊藤喜久: "Varied value of urinary N-acetyly-β-D-glucosaminidase isoenzyme B in males of reproductive age" Kidney International. Vol.46,Suppl.47. S-38-S-42 (1994)

Yoshihisa Ito：“育龄男性尿 N-乙酰基-β-D-氨基葡萄糖苷酶 B 的变化值”Kidney International 第 46 卷，增刊 S-38-S-42 (1994)。

Y.Itoh et al.: "Varied value of urinary NAG-B…" Kidney International. 46. S38-S42 (1994)

Y.Itoh 等人：“尿 NAG-B 的不同价值……”肾脏国际 46. S38-S42 (1994)。

Y.Itoh et al.: "Varied value of NAG-B in males of reproductive age" Kidney Int.46. S38-S42 (1994)

Y.Itoh 等人：“NAG-B 在育龄男性中的不同价值”Kidney Int.46。