To study the importance of the thiol function of mercaptoacetyltriglycine (MAG3) for complexing technetium, we investigated a number of derivatives wherein the thiol function of MAG3, is replaced by other metal binding groups such as 3-nitropropionyl, thiophene-2-carbonyl, pyrrole-2-carbonyl, acetoacetyl, hydroxyacetyl, picolyl or aminoacetyl. These groups have the potential to form a bond with Tc via a free electron pair or the loss of a proton. 3-Nitropropionyltriglycine, thiophene-2-carbonyltriglycine and pyrrole-2-carbonyl-triglycine were not able to form a single complex with 99mTc. Under the experimental conditions, acetoacetyltriglycine forms a rather unstable 99mTc-complex. On the other hand, the acetoacetyl group possesses sufficient complexing capacity to serve as the fourth coordination site of a tetraligand with a strongly technetium binding thiol and two amides. Hydroxyacetyltriglycine and derivatives of MAG3 in which the thiol group is substituted by an aromatic amine, as in picolyltriglycine, or an aliphatic amine, as in tetraglycine and other tetrapeptides, form complexes with technetium-99m which are stable for several hours. Copyright © 2001 John Wiley & Sons, Ltd.
为了研究巯基乙酰三甘
氨酸(MAG3)中巯基功能对于
锝络合的重要性,我们研究了一系列衍
生物,在这些衍
生物中,MAG3的巯基功能被其他
金属结合基团如
3-硝基丙酰基、
噻吩-2-羰基、
吡咯-2-羰基、乙酰乙酰基、羟基乙酰基、
吡啶基或
氨基乙酰基所替代。这些基团有可能通过自由电子对或质子的损失与
锝形成键。
3-硝基丙酰三甘
氨酸、
噻吩-2-羰基三甘
氨酸和
吡咯-2-羰基三甘
氨酸无法与99mTc形成单一络合物。在实验条件下,乙酰乙酰三甘
氨酸形成一个相对不稳定的99mTc-络合物。另一方面,乙酰乙酰基具有足够的络合能力,可以作为四
配体中与强
锝结合的巯基和两个酰胺的第四个配位点。羟基乙酰三甘
氨酸和MAG3的衍
生物,其中巯基被芳香胺如
吡啶基三甘
氨酸或脂肪胺如四甘
氨酸和其他四肽所替代,与
锝-99m形成可以稳定数小时的络合物。版权所有 © 2001 John Wiley & Sons, Ltd。