XVI International Botanical Congess

The quantification of total protein by analysis of total N depends on establishing specific nitrogen-to-protein conversion factors (N-Prot factors). We propose specific N-Prot factors for 4 Chlorophytes, 4 Phaeophytes and 9 Rhodophytes from Brazil. N-Prot factors were determined by relationship between the total N in the tissue and the content of N in total amino acid. Mean N-Prot factors were 5.05, 5.04, and 3.64 for green, brown and red algae respectively, lower than the traditional factor 6.25, used in the absence of specific N-Prot factors. Red algae have major amounts of non-protein compounds than green and brown algae. The factor 6.25 must be avoided, since it overestimates the actual protein content of seaweeds.