Robitaille P M, Abduljalil A, Rath D, Zhang H, Hamlin R L
Department of Medical Biochemistry, Ohio State University, Columbus.
Magn Reson Med. 1993 Jul;30(1):4-10. doi: 10.1002/mrm.1910300103.
31P NMR spatial localization and saturation transfer techniques were combined to enable the transmural measurement of the forward creatine kinase (CK) rate (ATP:creatine N-phosphotransferase, EC 2.7.3.2.) in the in vivo canine myocardium. Five epicardial towards endocardial regions of the left ventricle (LV) were simultaneously examined using spatially localized voxels. Although intraleft ventricular CP/ATP ratios were constant, the pseudo first order rate constant (k') and the forward creatine kinase rate (Rf) displayed a 61% variation across the LV wall. Because CK levels and calculated [ADP], [CP] and pH are transmurally invariant in the normal left ventricle, the observed changes in the Rf could not be explained by changes in the absolute levels of these substrates and of creatine kinase. In addition, because myocardial oxygen consumption rates are known to be higher in the endocardium, these results imply that forward creatine kinase rates are not directly related to oxidative phosphorylation rates.
采用³¹P核磁共振空间定位和饱和转移技术，实现了对活体犬心肌中正向肌酸激酶（CK）速率（ATP：肌酸N-磷酸转移酶，EC 2.7.3.2.）的跨壁测量。使用空间定位体素同时检查左心室（LV）从心外膜到心内膜的五个区域。尽管左心室内的CP/ATP比值恒定，但伪一级速率常数（k'）和正向肌酸激酶速率（Rf）在左心室壁上显示出61%的变化。由于在正常左心室中，CK水平以及计算得出的[ADP]、[CP]和pH值在跨壁时是不变的，因此观察到的Rf变化无法用这些底物和肌酸激酶的绝对水平变化来解释。此外，由于已知心内膜的心肌耗氧率较高，这些结果表明正向肌酸激酶速率与氧化磷酸化速率没有直接关系。
