We propose to study the dynamics of the central Fe spin in reduced model Fe-porphyrins. Our aim is to clarify a relatioship between the spin dynamics of Fe and functions of hemeproteins. We plan to measure the dynamic muon-spin depolarization rate of some model porphyrins changing temperatures and longitudinal fields in order to see changes of the fluctuation frequency of Fe spin. Due to difficulties of the sample preparation, we cound not carry out experiment before the long shut-down. This is the resubmittion of our proposal.