Abstract

The problem of the possible occurrence of silicon porphyrins in the living organisms has been put forward in the context of the hypothesis of siliceous life forms and the study of the molecular evolution of porphyrin systems. Some properties of the tetrapyrrole complexes of silicon as well as essential data and theories from domains of silicon biochemistry and paleobiochemistry have been reviewed.This has been a basis for doing some extrapolations and showing connections with bioelectronics, whereas some possible functions of hypothetical Si-porphyrins in biostructures, e.g. catalytic ones, have been shown. In the bioplasma concept, a possible use of Si-tetrapyrrole complexes as a model useful in the study of the plasma mechanism of enzymatic catalysis has been proposed, and a role of silicon analogues of chlorophyll-like compounds in primordial photosynthesis has been suggested.