Spanoghe M, Lanens D, Gorrebeeck C, Dommisse R, Lemière G, Van der Linden A, Van de Vyver F
Research Group for Biomedical NMR, University of Antwerp (UIA), Belgium.
Magn Reson Imaging. 1991;9(4):583-7. doi: 10.1016/0730-725x(91)90046-o.
The penetration of horse liver alcohol dehydrogenase (HLAD) molecules into polyacrylamide gel beads, which are used to immobilize the enzyme, was studied. HLAD was labeled with gadolinium diethylene-triamine-pentaacetic acid (Gd-DTPA), using the N-hydroxy-succinimide active ester of DTPA as a chelating agent. The HLAD-(Gd-DTPA)27 has a 3.7-fold larger longitudinal (R1) and a 14-fold larger transversal relaxivity (R2) (at 2.4 T) than the plain Gd-DTPA. A series of dry polyacrylamide gel beads, with total monomer concentration ranging from 5% to 30% were synthesized and swollen in a buffered solution of HLAD-(Gd-DTPA)27. The gel beads were examined with high resolution NMR imaging. The T1- and T2-weighted images revealed that the permeability for the labeled HLAD decreased with increasing total monomer concentration of the gel beads. These imaging results correlate fairly well with the enzymatic reactivities measured for the same range of gel beads but swollen in a solution of non labeled HLAD and NAD+ (nicotinamide adenine dinucleotide). It is concluded that Gd-labeling can be used to monitor the distribution of weakly concentrated, water soluble products in a solid matrix.
研究了马肝醇脱氢酶（HLAD）分子渗透到用于固定该酶的聚丙烯酰胺凝胶珠中的情况。使用二乙三胺五乙酸（DTPA）的N-羟基琥珀酰亚胺活性酯作为螯合剂，用钆二乙三胺五乙酸（Gd-DTPA）标记HLAD。与普通的Gd-DTPA相比，HLAD-(Gd-DTPA)27在纵向（R1）的弛豫率大3.7倍，在横向（R2）的弛豫率大14倍（在2.4 T时）。合成了一系列总单体浓度范围为5%至30%的干燥聚丙烯酰胺凝胶珠，并在HLAD-(Gd-DTPA)27的缓冲溶液中溶胀。用高分辨率核磁共振成像对凝胶珠进行检查。T1加权和T2加权图像显示，标记的HLAD的渗透率随着凝胶珠总单体浓度的增加而降低。这些成像结果与在相同范围的凝胶珠中测量的酶活性相当吻合，这些凝胶珠在未标记的HLAD和烟酰胺腺嘌呤二核苷酸（NAD+）溶液中溶胀。得出的结论是，钆标记可用于监测固体基质中低浓度水溶性产物的分布。
