Hampton A, Picker D, Nealy K A, Maeda M
J Med Chem. 1982 Apr;25(4):382-6. doi: 10.1021/jm00346a010.
Adenosine 5'-triphosphate (ATP) derivatives of the types N6-R-ATP [R = (CH2)nHNCOCH2I, (CH2)nNHCO-(CH2)mHNCOCH2I, or (CH2)nCON(Me)(CH2)mN(Me)CO(CH2)nNHCOCH2I], N6-Me-N6-R-ATP [R = (CH2)nN-(Me)CO(CH2)mNHCOCH2I], and 8-R-ATP [R = NH(CH2)nNHCOCH2I] with 5--19 spacer atoms between N6 or C-8 and iodine have been evaluated as substrates, reversible inhibitors, and inactivators of adenylate kinase (AK). With Escherichia coli AK, the derivatives were noncompetitive inhibitors, Ki = 4.7--7.3 mM, with little affinity for the ATP site, and N6-(CH2)nNHCOCH2[-ATP (n = 5 or 6) effected progressive inhibitions that were not ATP site directed. With rat muscle AK (M-AK), some compounds had slight affinity for the ATP site as evidenced by weak substrate activity with as much as 8 spacer atoms, but all compounds tested were weak noncompetitive inhibitors; Ki = 6--12 mM vs. ATP. The ATP derivatives, notably N6-(CH2)8NHCOCH2I-ATP, mediated a progressive inhibition of M-AK, which was abolished by substitution of hydrogen for the iodine and thus presumably involves alkylation of the enzyme. The inhibition appeared not to be ATP site directed because kinetic analysis indicated a random bimolecular enzyme-inhibitor reaction and because N6-(CH2)8NHCOCH2I-AMP and its adenosine counterpart, which have relatively low affinity for the ATP site, were more effective than N6-(CH2)8NHCOCH2I-ATP. The ATP derivatives were substrates (KM = 0.4--1.6 mM) and/or competitive inhibitors (Ki = 0.3--6.2 mM) vs. ATP of rat isozymes AK II or III. Exposure of AK II or III for 6 h, 22 degrees C, at pH 7.6 to 10 mM levels of the 1:1 Mg complexes of 25 of the ATP derivatives led in no case to progressive enzyme inhibition, suggesting the absence near the ATP sites of nucleophilic groups suitably positioned for alkylation.
已对N6 - R - ATP [R = (CH2)nHNCOCH2I、(CH2)nNHCO - (CH2)mHNCOCH2I或(CH2)nCON(Me)(CH2)mN(Me)CO(CH2)nNHCOCH2I]、N6 - Me - N6 - R - ATP [R = (CH2)nN - (Me)CO(CH2)mNHCOCH2I]和8 - R - ATP [R = NH(CH2)nNHCOCH2I] 这类腺苷5'-三磷酸（ATP）衍生物进行了评估，它们在N6或C - 8与碘之间有5 - 19个间隔原子，可作为腺苷酸激酶（AK）的底物、可逆抑制剂和失活剂。对于大肠杆菌AK，这些衍生物是非竞争性抑制剂，Ki = 4.7 - 7.3 mM，对ATP位点亲和力很小，且N6 - (CH2)nNHCOCH2[-ATP（n = 5或6）产生的渐进性抑制并非针对ATP位点。对于大鼠肌肉AK（M - AK），一些化合物对ATP位点有轻微亲和力，多达8个间隔原子时具有微弱底物活性可证明这一点，但所有测试化合物均为弱非竞争性抑制剂；相对于ATP，Ki = 6 - 12 mM。ATP衍生物，尤其是N6 - (CH2)8NHCOCH2I - ATP，介导了对M - AK的渐进性抑制，用氢取代碘后这种抑制作用消除，因此推测涉及酶的烷基化。这种抑制似乎不是针对ATP位点的，因为动力学分析表明是随机双分子酶 - 抑制剂反应，而且对ATP位点亲和力相对较低的N6 - (CH2)8NHCOCH2I - AMP及其腺苷类似物比N6 - (CH2)8NHCOCH2I - ATP更有效。ATP衍生物是大鼠同工酶AK II或III相对于ATP的底物（KM = 0.4 - 1.6 mM）和/或竞争性抑制剂（Ki = 0.3 - 6.2 mM）。在22℃、pH 7.6条件下，将AK II或III暴露于25种ATP衍生物的1:1镁络合物的10 mM水平6小时，未导致酶的渐进性抑制，这表明在ATP位点附近不存在适合烷基化的亲核基团。
