The structure of the early metabolic network is unknown. In this Perspective, the authors report that #pentose utilization pathways form all life-essential precursors, speculating that pentose #metabolism could have been a central structural element in early metabolism.
plos.io/3BWz68q
Shedding light on the synthesis of sugars before the origin of life

Pentoses are essential carbohydrates in the metabolism of modern lifeforms, but their availability during early Earth is unclear since these molecules are unstable.

Phys.org