KINETIC PROPERTIES OF MUTANT HOLOCARBOXYLASE SYNTHETASES

突变型全羧化酶合成酶的动力学特性

• 批准号: 10470172
• 负责人: NARISAWA Kuniaki
• 金额: $ 8.26万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10470172/
• 关键词: BIOTIN; HOLOCARBOXYLASE SYNTHETASE DEFICIENCY; MUTATION; KINETICO; MULTIPLE CARBOXYLASE DEFICIENCY; Vmax値; 開始コドン; ペプチド抗体; ウエスタンブロット; ピオチン反応性

Holocarboxylase synthetase (HCS) deficiency is a metabolic disorder causing a biotin-responsive multiple carboxylase deficiency. We analyzed the kinetic property of several mutant HCS proteins. Two mutants located within the putative biotin-binding site of HCS showed elevated Km values for biotin compared to those of the wild-type form. On the other hand, the remaining five mutations were outside of the biotin-binding site. The enzymes containing these mutations showed normal or low Km values for biotin (non-Km mutant). Symptoms of patients who have the non-Km mutants, as well as those of patients who have the Km mutants, responded to biotin therapy. The responsiveness to biotin supplement of propionyl-CoA carboxylase activity in cultured cells bearing some of these mutations correlated well to the corresponding reduction in the Vmax. Patients who have mutant HCS proteins with lower Vmax showed poor clinical and biochemical responses to biotin therapy. The determination of HCS genotype can be valuable for characterizing the clinical phenotype in HCS deficient patients.

全羧化酶合成酶（HCS）缺乏症是一种代谢紊乱，导致生物素反应性多种羧化酶缺乏症。我们分析了几种突变型 HCS 蛋白的动力学特性。与野生型相比，位于 HCS 假定生物素结合位点内的两个突变体显示出较高的生物素 Km 值。另一方面，其余五个突变位于生物素结合位点之外。含有这些突变的酶显示出正常或较低的生物素 Km 值（非 Km 突变体）。具有非 Km 突变体的患者以及具有 Km 突变体的患者的症状对生物素治疗有反应。在带有某些突变的培养细胞中，丙酰辅酶A羧化酶活性对生物素补充的反应与Vmax的相应降低密切相关。具有 Vmax 较低的突变 HCS 蛋白的患者对生物素治疗的临床和生化反应较差。 HCS 基因型的测定对于表征 HCS 缺陷患者的临床表型非常有价值。

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