Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) fixes atmospheric CO₂ into organic compounds and is composed of eight copies each of a large subunit (RbcL) and a small subunit (RbcS). Recent reports have revealed unusual RbcS, which are expressed in particular tissues and confer higher catalytic rate, lesser affinity for CO₂, and a more acidic profile of the activity versus pH. The resulting Rubisco was proposed to be adapted to a high CO₂ environment and recycle CO₂ generated by the metabolism. These RbcS belong to a cluster named T (for trichome), phylogenetically distant from cluster M, which gathers well-characterized RbcS expressed in mesophyll or bundle-sheath tissues. Cluster T is largely represented in different plant phyla, including pteridophytes and bryophytes, indicating an ancient origin.

ř IB ü输-1,5-双磷酸Ç arboxylase / ø xygenase酶（Rubisco）的修复大气中的CO ₂进入的有机化合物和由每一个大亚基（rbcL基因）和一个小亚基基因（rbcS）的八个拷贝。最近的报道揭示了不寻常的RbcS，它在特定的组织中表达并具有较高的催化速率，对CO _2的亲和力较小，并且活性相对于pH呈酸性。建议将所得的Rubisco应用于高CO ₂环境并回收CO ₂由新陈代谢产生。这些RbcS属于一个名为T（对于毛状体）的簇，在系统发育上与簇M远离，该簇聚集了在叶肉或束鞘组织中表达的特征明确的RbcS。簇T主要存在于不同的植物门类中，包括蕨类植物和苔藓植物，表明其起源很久。