On the reactivity of hemoglobin MIwate

Motokawa, Yutaro; Hayashi, Norio; Kikuchi, Gorö

doi:10.1016/0003-9861(64)90058-x

Cited by 17 publications

(8 citation statements)

References 13 publications

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“…Motokawa (3) reported that skin potential in chloride Ringer's decreased when urea, glucose, or sucrose was added to the outside bathing solution. The above order was the order of decreasing effectiveness for depressing skin potential when full strength Ringer's was used to dissolve the solutes.…”

Section: Discussionmentioning

confidence: 99%

Effects of D2O and Osmotic Gradients on Potential and Resistance of the Isolated Frog Skin

Lindley

Hoshiko

Leb

1964

The Journal of General Physiology

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A B S T R A C T Exposure of the outside surface of isolated frog skin (R. pipiens and R. catesbeiana) to sulfate solution made up with D,O decreased skin potential and resistance. Exposure of the inside surface to D,O solution decreased the potential slightly but increased the resistance. The changes were linearly related to the D20 concentration. Since D,O acts like a hyperosmotic solution, the skin potential and resistance were studied upon exposure to solution made hyperosmotic by addition of sucrose, mannitol, acetamide, urea, thiourea, Na,SO,, or K~SO4. Skin potential and resistance decreased when the outside solution was made hyperosmotic. The changes depended upon the concentration and the nature of the solute. Thiourea and urea solutions were the most effective. Treatment of the inside surface gave relatively small decreases in potential; the resistance either increased or remained unchanged. These effects appeared to depend upon the direction of the osmotic gradient across the skin rather than upon the value of the osmolarity compared to normal body fluids. Experiments with a series of six polyhydric alcohols from methanol to mannitol and the polysaccharides, sucrose and raffmose, showed adonitol with 5 carbons to decrease the potential the most. Smaller and larger compounds of this set gave lesser effects. As yet no consistent explanation of the effects is forthcoming, but their demonstration calls for caution in the indiscriminate use of solutes such as mannitol or sucrose "to make up the osmolality" and in the neglect of urea because "it penetrates freely." I N T R O D U C T I O NIn 1939 T. C. Barnes (1) reported experiments in which he replaced the inside and outside solutions bathing frog skin with D~O Ringer's (chloride). He observed large decreases in potential. In our initial experiments with D~O effects on frog skin the magnitude of the depression depended upon which side of the skin was exposed to D20: outside exposure gave the largest depression, inside exposure gave the least depression, and simultaneous exposure 773

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Section: Discussionmentioning

confidence: 99%

Effects of D2O and Osmotic Gradients on Potential and Resistance of the Isolated Frog Skin

Lindley

Hoshiko

Leb

1964

The Journal of General Physiology

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“…Further changes in spectra did not occur during the period of 2-4 days in which the sample was run. After each run the spectrum of the CO-ligated hemoglobin was checked to verify that oxidation had not occurred and that the typical CO spectrum (Motokawa et al, 1964) persisted. Reduction of both the ß and the a chains was accomplished by addition of a molar excess of sodium dithionite to the deoxygenated sample at 4°and waiting until the spectrum characteristic of full reduction, similar to that of deoxygenated Hb A, was obtained.…”

Section: Methodsmentioning

confidence: 99%

“…This critical residue occupies the fifth coordination site of the heme iron. The change of this proximal histidine to tyrosine produces substantial changes in the ligand binding properties of the heme iron (Motokawa et al, 1964;Hayashi et al, 1966Hayashi et al, , 1967Hayashi et al, , 1968Gersonde et al, 1973). In particular, oxygen rapidly oxidizes the «-chain irons of Hb M Iwate to the ferric state which in vivo cannot be reduced by the methemoglobin reductase (Hayashi et al, 1966).…”

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confidence: 99%

Heats of carbon monoxide binding by hemoglobin M Iwate

Ht¹,

Sj²,

Bg³

et al. 1975

Biochemistry

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The heat of reaction of CO gas with the alpha2Mmetbeta2 and alpha2Mbeta2 species of the alpha-chain mutant hemoglobin M Iwate has been studied in buffers with different heats of ionization of 25degrees and in the absence of organic phosphates. For the alpha2Mmetbeta2deoxy species we find a small Bohr effect (0.12 mol of H+/mol of CO) which is in correspondence with that found in equilibrium studies. The heat of reaction, when corrected for proton reaction with buffer, is -18.4 +/- 0.3 kcal/mol of CO at pH 7.4 At pH 9 the same value is observed within experimental error. This value compares closely with heats of reaction of CO with myoglobin and with van't Hoff determinations of the heat of oxygen binding to isolated hemoglobin alpha and beta chains after correction for the heat of replacement of O2 by CO. Furthermore, an analysis of the differential heat of ligand binding as a function of the extent of reaction indicated that, within experimental error, the heat of reaction with the first beta-chain heme in alpha2Mmetbeta2deoxy is the same as the second. Since the quaternary Tleads to R transition is blocked in this mutant hemoglobin, we compared it with Hb A to estimate the enthalpic component of the allosteric T leads to R transition in Hb A. The heats of reaction with CO(g) and Hb A are -15.7 +/- 0.5 and -20.9 +/- 0.5 kcal/mol at pH 7.4 and 9.0, respectively. In going from the T to the R state we find an enthalpy of transition of 9 +/- 2.5 kcal at pH 7.4 and -12 +/- 2.5 kcal at pH 9.0. From published free energies of transsition we conclude the T leads to R transition is enthalpically controlled at p/ 7.4 but entropically controlled at pH 9.0 A near normal Bohr effect is estimated from heats of reaction of CO with alpha2Mdeoxybeta2deoxy in various buffers. A large than normal heat of reaction (-21.6 +/- 0.5 kcal/mol of CO) is attributed to the abnormal alpha chains in Hb M Iwate.

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“…It has been known for some time that the composition of the bathing fluids determines, at least in part, the frog skin potential (e.g. see Motokawa (7,8) ). Thus, it was mentioned by Dean and Gatty (9) that R b and Cs depolarized frog skin.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Alkali Metal Cations and Common Anions on the Frog Skin Potential

Lindley

Hoshiko

1964

The Journal of General Physiology

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The effects on the potential difference across isolated frog skin (R. catesbeiana, R. pipiens) of changing the ionic composition of the bathing solutions have been examined. Estimates of mean values and precision are presented for the potential changes produced by substituting other alkali metal cations for Na at the outside border and for K at the inside border. In terms of ability to mimic Na at the outside border of bullfrog skin, the selectivity order is Li > Rb, K, Cs; at the outside border of leopard frog skin, Li > Cs, K, Rb. In terms of ability to mimic K at the inside border of bullfrog and leopard frog skin: Rb > Cs > Li ~ Na. Orders of anion selectivity in terms of sensitivity of the potential for the outside border of bullfrog skin are Br ~ C1 > NOs > I > SO4, isethionate and of leopard frog skin are Br, C1 > I, NOs, SO4. An effect of the solution composition (ionic strength?) on the apparent Na-K selectivity of the outside border is described. The results of the investigation have been interpreted and discussed in terms of the application of the constant field equation to the Koefoed-Johnsen-Ussing frog skin model. These observations may be useful in constructing and testing models of biological ionic selectivity. I N T R O D U C T I O NIn the recent literature, models of selectivity for alkali metal cations have appeared (1, 2). Inasmuch as such suggestions appear to offer pathways toward a more fundamental understanding of the basis of bioelectric phenomena, an attempt to furnish data for testing the validity of the hypotheses is in order. Experimental work with the alkali metal cations has a long history (3, 4), but there is a scarcity of studies in which members of the series have been quantitatively compared under conditions formulated in the light of modern theories of bioelectric phenomena (but see Sjodin (5, 6) on frog skeletal muscle).The suitability of frog skin for such a study lies in two facts. It maintains a 749

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On the reactivity of hemoglobin MIwate

Cited by 17 publications

References 13 publications

Effects of D2O and Osmotic Gradients on Potential and Resistance of the Isolated Frog Skin

Effects of D2O and Osmotic Gradients on Potential and Resistance of the Isolated Frog Skin

Heats of carbon monoxide binding by hemoglobin M Iwate

The Effects of Alkali Metal Cations and Common Anions on the Frog Skin Potential

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