Iseki K, Mori K, Miyazaki K, Arita T
Biochem Pharmacol. 1987 Jun 1;36(11):1843-6. doi: 10.1016/0006-2952(87)90248-6.
The characteristics of binding of amino beta-lactam antibiotics including ampicillin, amoxicillin, cephalexin and cephradine to fraction b obtained from the 105,000 g supernatant of rat small intestinal mucosa was investigated. The mutual inhibition of binding among these antibiotics was observed, and these were dependent on the concentration of inhibitors. It was found that dipeptides such as L-carnosine and glycylglycine significantly reduced the binding of cephalexin to fraction b, but the binding of cephradine was only slightly decreased by these dipeptides. Furthermore, the binding of cephalexin and cephradine was not influenced by amino acids (L-phenylalanine, glycine). Although ANS(1-anilino-8-naphthalenesulfonic acid magnesium salt), which is a hydrophobic probe, bound to the fraction b, there was no competitive inhibition in binding between ANS and amino beta-lactam antibiotics. The Scatchard plot of binding data of cephalexin gave two dissociation constant (Kd) values (1.37 and 15.7 microM). On the other hand, one Kd value (11.2 microM) was obtained for ampicillin.
研究了包括氨苄西林、阿莫西林、头孢氨苄和头孢拉定在内的氨基β-内酰胺类抗生素与从大鼠小肠黏膜105,000 g上清液中获得的组分b的结合特性。观察到这些抗生素之间存在结合的相互抑制作用，且这取决于抑制剂的浓度。发现诸如L-肌肽和甘氨酰甘氨酸等二肽显著降低了头孢氨苄与组分b的结合，但这些二肽仅略微降低了头孢拉定的结合。此外，头孢氨苄和头孢拉定的结合不受氨基酸（L-苯丙氨酸、甘氨酸）的影响。尽管作为疏水探针的1-苯胺基-8-萘磺酸镁盐（ANS）与组分b结合，但在ANS与氨基β-内酰胺类抗生素的结合中不存在竞争性抑制。头孢氨苄结合数据的Scatchard图给出了两个解离常数（Kd）值（1.37和15.7 microM）。另一方面，氨苄西林获得了一个Kd值（11.2 microM）。
