Respiration and Alanine Metabolism in Commelina Epidermis

Abstract

[U-¹⁴C]alanine offered to epidermal peels was readily metabolized, mostly via pyruvate and the tricarboxylic acid cycle. Some two-thirds of the radioactivity absorbed was respired and some 2-4% converted to sucrose and ethanol-insoluble compounds. Nevertheless, the calculated amounts of alanine respired were much less than expected. Despite a large degree of deamination and reamination, the fate of the imported amino acid groups is unknown but we believe they are re-exported to the mesophyll, possibly as aspartate during stomatal closing.