Sato H, Yamakawa Y, Ito A, Murata R
Infect Immun. 1978 May;20(2):325-33. doi: 10.1128/iai.20.2.325-333.1978.
Clostridium perfringens produced at least three distinct proteases in a synthetic medium containing calcium. Two of them, thiol and ethylenediaminetetraacetic acid disodium salt-sensitive proteases, appeared at an early stage of growth, but the other one, perhaps being identical to the one produced in a calcium-deficient medium, appeared at a late stage. The production of these proteases depended on Ca2+ but not on Zn2+ in the medium. Alpha-toxin, perhaps being a zinc-containing metalloenzyme, was rather resistant to the proteases, but toxin, produced in a zinc-deficient medium or deprived of zinc with ethylenediaminetetraacetic acid disodium salt, was very sensitive. By adding Zn2+, the toxin lacking zinc may have been converted to the zinc-containing metalloprotein that is resistant to proteases. This may explain why alpha-toxin activity increased progressively in a zinc-containing medium in spite of simultaneous production of potent proteases and why it disappeared rapidly in a zinc-deficient medium.
产气荚膜梭菌在含有钙的合成培养基中至少产生三种不同的蛋白酶。其中两种，即对硫醇和乙二胺四乙酸二钠盐敏感的蛋白酶，在生长早期出现，但另一种蛋白酶，可能与在缺钙培养基中产生的蛋白酶相同，在生长后期出现。这些蛋白酶的产生取决于培养基中的Ca2+，而不取决于Zn2+。α毒素可能是一种含锌金属酶，对这些蛋白酶具有相当的抗性，但在缺锌培养基中产生的毒素或用乙二胺四乙酸二钠盐去除锌的毒素则非常敏感。通过添加Zn2+，缺乏锌的毒素可能已转化为对蛋白酶具有抗性的含锌金属蛋白。这可以解释为什么尽管同时产生了强效蛋白酶，α毒素活性在含锌培养基中仍逐渐增加，以及为什么它在缺锌培养基中迅速消失。
