Sykes R B, Nordström K
Antimicrob Agents Chemother. 1972 Feb;1(2):94-9. doi: 10.1128/AAC.1.2.94.
The product of beta-lactamase activity (a penicilloic acid in the case of a penicillin) is stoichiometrically oxidized by iodine. Hence, the beta-lactamase activity can be measured as decolorization of the blue starch-iodine complex. Since the decolorization is a slow process, the rate of decolorization gave an underestimate of the rate of penicillin hydrolysis until a steady state was obtained after 15 to 20 min. If the reaction mixture (3 ml) contained no more than 0.001 unit of enzyme, a correct determination of beta-lactamase activity was obtained from the microiodometric method described. The method is sensitive and some applications are mentioned.
β-内酰胺酶活性的产物（青霉素的情况下为青霉噻唑酸）可被碘按化学计量比氧化。因此，β-内酰胺酶活性可通过蓝色淀粉-碘复合物的脱色来测定。由于脱色是一个缓慢的过程，在15至20分钟达到稳态之前，脱色速率会低估青霉素水解的速率。如果反应混合物（3毫升）中酶的含量不超过0.001单位，则可通过所述的微量碘量法正确测定β-内酰胺酶活性。该方法灵敏，并提及了一些应用。
