Phosphate immobilization by oxide precursors: implications on phosphate availability before life on earth.
The present study is based on the proposal that if the aqueous phosphorus-capture mechanism by iron oxide precursors was inhibited in prebiotic anoxic scenarios then soluble phosphates could have been more available than what is observed now. Supporting this conjecture, we examine prevailing contemporary trapping mechanisms of orthophosphate (Pi) and pyrophosphate (PPi). To illustrate its efficiency, the attachment of (Pi) onto aggregates of iron-3 oxyhydroxide is compared with the one reported for the product of its condensation, PPi. The electrophoretic profiles of the Pi- and PPi-aggregate complexes reveal different pH-modulated interactions of the phosphorylated compounds with both the aggregate and its aqueous surrounding layers. The observed differences of Pi/PPi sorption and desorption mechanisms are discussed in terms of their consequences to the prebiotic availability of soluble orthophosphate and of a phosphorylated compound having the high-energy phosphoanhydride linkage and a molecule representative of condensed oligophosphates.
Monte
Marisa B M
MB
Centro de Tecnologia Mineral (CETEM), Ministério da Ciência e da Tecnologia, Rio de Janeiro, Brasil.
Duarte
Ana C P
AC
Bonapace
José A P
JA
Do Amaral
Manoel R
MR
Vieyra
Adalberto
A
De Souza-Barros
Fernando
F
D011756:Diphosphates / Q000737:chemistry*; D004586:Electrophoresis; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D010710:Phosphates / Q000737:chemistry*; D013997:Time Factors; D014961:X-Ray Diffraction
D011756:Diphosphates; D005290:Ferric Compounds; D010710:Phosphates; C000499:ferric oxide