Which molecule is believed to have acted as the first enzyme in the early development of life on Earth?

The belief that RNA acted as the first enzyme in the early development of life stems from the RNA world hypothesis. This hypothesis suggests that before DNA and proteins became the predominant molecules for genetic information and catalysis, RNA played critical roles in both processes. RNA has the unique capability to store genetic information like DNA while also possessing catalytic properties like proteins. This dual functionality allows RNA to serve as both a carrier of information and a catalyst for chemical reactions.

In this early primordial environment, the ability of RNA to self-replicate and facilitate biochemical reactions would have provided a plausible mechanism for the origin of life. Subsequently, the evolution of more stable DNA and more efficient proteins would have taken place, leading to the complexity of life we see today. Thus, RNA is considered the likely candidate for the first enzyme that catalyzed the early biochemical processes necessary for life’s emergence. In contrast, DNA, proteins, and carbohydrates do not possess the same combination of informational and catalytic properties, making them less likely to have been the first enzymes in the development of life.