The earliest catabolic pathways.

Anaerobic catabolism of amino acids may have provided the main source of energy for primitive microorganisms. Examples are given of amino acid catabolic reactions coupled to substrate level phosphorylations occurring in present-day anaerobes which may be biochemical fossils from a very early stage of the evolution of procaryotes.

Amino acid utilization patterns in clostridial taxonomy.

The polyamide layer technique for the chromatographic separation of dimethylaminonaphthalene sulphonyl amino acids has been adapted to the qualitative analysis of amino acids in media before and after the growth of micro-organisms. The method has been used to study the amino acids metabolized by cultures of proteolytic clostridia growing in a medium consisting of an acid hydrolysate of casein as a source of amino acids and small amounts of yeast extract and trypticase as sources of growth factors. The chromatograms of the media after growth showed which amino acids were used and which new amino acids were produced.

The end products of the metabolism of aromatic amino acids by Clostridia.

The end products of the metabolism of phenylalanine, tyrosine and tryptophan by growing cultures of clostridia have been identified. The species used were Clostridium aminovalericum; C. bifermentans; C.

The synthesis of amino acids by Methanobacterium omelianskii.

1. Methanobacterium omelianskii was grown on (14)CO(2) and unlabelled ethanol, or on [1-(14)C]- or [2-(14)C]-ethanol and unlabelled carbon dioxide. The cell protein was hydrolysed and certain of the amino acids were isolated and degraded.