An Intracellular Protein Intermediate for Hemoglobin Formation*

Greenough, William B.; Peters, Theodore; Thomas, E. Donnall

doi:10.1172/jci104563

Cited by 31 publications

(10 citation statements)

References 17 publications

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“…At the surface of the red cell precursor it is released from transferrin onto the cell membrane and is incorporated rapidly into hemoglobin (1)(2)(3)(4). The mechanism of the movement of iron from the cell membrane to the site of hemoglobin synthesis is not understood.…”

Section: Introductionmentioning

confidence: 99%

“…The mechanism of the movement of iron from the cell membrane to the site of hemoglobin synthesis is not understood. Several studies have indicated that iron enters a nonheme precursor before being incorporated into hemoglobin (3)(4)(5)(6)(7). Some reports have suggested that ferritin is an intracellular precursor of hemoglobin (8,9).…”

Section: Introductionmentioning

confidence: 99%

“…Marrow was obtained from the long bones and suspended in Ringer's solution. The marrow was sieved through a stainless steel tea strainer and then passed through a stainless steel screen with openings 200 a square (4). Fat was removed by centrifugation at 240 g. The marrow was processed and used within 1 hr after removal from the body.…”

Section: Introductionmentioning

confidence: 99%

“…The hemoglobin solution was chromatographed on the cation exchange resin, Amberlite IRC-50, (Rohm and Haas, Philadelphia, Pa.) in two steps as previously described (4). The first fraction composed of heterogeneous compounds not adsorbed to IRC-50 was referred to as "fraction I."…”

Section: Introductionmentioning

confidence: 99%

“…The cells were washed with Ringer's solution and lysed with distilled water. The ultracentrifuged lysate was chromatographed on Amberlite IRC-50 to remove the main hemoglobin component (4). The unadsorbed protein mixture (fraction I) was separated by means of a DEAE column into four peaks ( Fig.…”

Section: Introductionmentioning

confidence: 99%

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Studies on the partition of iron in bone marrow cells

Primosigh¹,

Thomas²

1968

J. Clin. Invest.

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A B S T R A C T Canine marrow cells were incubated with transferrin-bound 59Fe, and the partition of cellular iron was studied by chromatographic and gel filtration methods. Splitting-off of iron from the stromal fraction was avoided by lysing the cells in Tris HCl buffer at pH 8.6. Cellular iron was divided into four major compartments: stroma, microsomes, main hemoglobin, and fraction I. The iron in fraction I was found in ferritin, heme proteins, and low molecular weight iron.With incubation times of 3-10 min, 59Fe appeared promptly in the main hemoglobin. The entry of 59Fe into ferritin paralleled that of hemoglobin but was smaller in amount. When the marrow cells were incubated with 59Fe for 15-20 min and reincubated without radioactive iron, movement of 59Fe into main hemoglobin was observed, and essentially all this iron came from the particulate fraction (stroma, mitochondria, and microsomes). In these chase experiments there was no change in the total quantity of 59Fe in ferritin. There was no evidence of a significant hemoglobin precursor other than low molecular weight iron.Depending upon concentration, lead was observed to inhibit cellular iron metabolism at several points: uptake of iron by the cell, movement of iron from stroma to the soluble intracellular compartment, and synthesis of hemoglobin. The most pronounced inhibitory effect of lead was always on hemoglobin synthesis with an increase in ferritin: hemoglobin ratio. Bipyridine appeared to trap intracellular ferrous iron and to inhibit synthesis of both hemoglobin and ferritin.

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Section: Introductionmentioning

confidence: 99%