Measurements of paramagnetic susceptibility on a red and a green complex of ferriheme with poly-L-lysine in aqueous solution, indicate that low-spin complexes are formed. For the red complex it is assumed that two [image]-amino groups are bound to each porphyrin iron. Molecular models suggest that these two [image]-amino groups originate from different polypeptide molecules. With these results the previously established spectral analogies between ferricytochrome c and the red polylysine complex are now extended to include similarities in.the postualted mode of binding of the heme in both cases.