Rm. Daniel et Mj. Danson, DID PRIMITIVE MICROORGANISMS USE NONHEM IRON PROTEINS IN-PLACE OF NADP/, Journal of molecular evolution, 40(6), 1995, pp. 559-563
Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinuc
leotide phosphate (NADP) are of universal occurrence in living organis
ms and play a central role in coupling oxidative with reductive reacti
ons. However, the evidence that the origin and early evolution of Life
occurred at high temperatures (>95 degrees C) is now strong, and at t
hese temperatures some modern metabolites, including both the reduced
and oxidized forms of these coenzymes, are unstable. We believe there
is good evidence that indicates that in the most primitive organisms n
onhem iron proteins carried out many or all of the functions of NAD/P(
H). This has important implications for the way in which investigation
s of archaebacterial metabolism are conducted.