146 A. ROSSI-FANELLI, E. ANTONINI, D. POVOLEDO [9 



The most important chemical and physico-chemical properties of Aplysia 

 Mb compared with mammalian Mb, are summarized in Table 2. The data 

 show that the pigment isolated from Aplysia is very similar to mammalian 

 myoglobins with respect to molecular weight, haem content, the shape of 

 the oxygen dissociation curve and the absence of the Bohr effect. On the 

 other hand, Aplysia Mb shows some characteristic features, namely absorp- 

 tion spectra, 'span', relative affinity for CO and O2, isoelectric point and 

 chemical nature of globin, that strongly differentiate this pigment from all 

 the known myoglobins. 



Table 1 



AMINO ACID COMPOSITION OF APLYSIA 



DEPILANS MYOGLOBIN AND HUMAN 



MYOGLOBIN 



(Average values of three determinations) 

 Grams amino acid per 100 g. of protein 



