. Currents in biochemical research, 1956; twenty-seven essays charting the present course of biochemical research and considering the intimate relationship of biochemistry to medicine, physiology, and biology. Biochemistry -- Research. DAVID SHEMIN give rise to a prophyrin of the III series. In the formation of the porphyrin of the III series it can be seen from Figure 6 that it is necessary to lose a one-carbon atom compound, since there are three aminomethyl side chains and only two are required to condense the two dipyrroles to the porphyrin structure. If the mechanism similar to that outli
. Currents in biochemical research, 1956; twenty-seven essays charting the present course of biochemical research and considering the intimate relationship of biochemistry to medicine, physiology, and biology. Biochemistry -- Research. DAVID SHEMIN give rise to a prophyrin of the III series. In the formation of the porphyrin of the III series it can be seen from Figure 6 that it is necessary to lose a one-carbon atom compound, since there are three aminomethyl side chains and only two are required to condense the two dipyrroles to the porphyrin structure. If the mechanism similar to that outlined in Figure 6 is concerned with porphyrin synthesis, it would appear that this one-carbon atom compound given off could well be formaldehyde. Consistent with this idea is our finding (29) that on the conversion of por- Ac NH2CH2'\ /". / \ CHgNHj Ac CH2-NH2 'Acelic ocid side chom Propionic acid side chain °(- carbon atom of glycine and J - carbon atom of /{-aminolevulinic acid Fig. 6. A mechanism of porphyrin formation from the monopyrrole. phobilinogen to porphyrins either by heating under acid con- ditions (32) or by enzymatic conversion in cell-free extracts (23,29) formaldehyde was formed. This was established by heating or incubating porphobilinogen, labeled with C^"* in the aminomethyl group, and subsequently isolating radioactive formaldehyde as the dimedon derivative. It would appear that on conversion of porphobilinogen to porphyrins, formaldehyde from the aminomethyl group is formed and that any postulated mechanism should take this into consideration. It is difficult at present to establish the structure of the intermediate tetrapyrrole compounds which are formed prior to the formation of protoporphyrin. However, we would like to suggest that these intermediate tetrapyrrole compounds may be in a more highly reduced state, containing 532. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabil
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