Compulsory voting , 22 countries were recorded as having compulsory voting. Of these, only 10 countries (additionally one Swiss canton and one Indian state) enforce it. Of the 30 member states of the Organisation for Economic Co-operation and Development, 10 had forms of compulsory voting. These are the countries and sub-national entities that enforce compulsory voting: Countries that have compulsory voting by law but do not enforce it: Although voting in a country may be compulsory, penalties for failing to vote are not always strictly enforced. In Australia and Brazil, providing a legitimate reason for not voting (such as illness) is accepted.
Catalytic triad Within protease superfamilies that contain a mixture of nucleophiles (e.g. the PA clan), families are designated by their catalytic nucleophile (C=cysteine proteases, S=serine proteases). A further subclass of catalytic triad variants are pseudoenzymes, which have triad mutations that make them catalytically inactive, but able to function as binding or structural proteins. For example, the heparin-binding protein Azurocidin is a homolog of PA clan, but with a glycine in place of the nucleophile and a serine in place of the histidine. Similarly, RHBDF1 is a homolog of the S54 family rhomboid proteases with an alanine in the place of the nucleophilic