ALBERT

Notes: [Auszug] Spanswick does not seem to have understood fully the theories under consideration5?8. (The theory of selective adsorption on protein sites as the mechanism for K+ ion accumulation in living cells was first proposed by me in 19517,8 and was known for some time as the "fixed charge hypothesis" until ...

Notes: Abstract A theory of the cell volume is presented with emphasis on the swelling effect of high concentrations of KCl and other chloride salts. In this theory a particular cell volume represents a state of balance between the tendency of the cell water to build deeper layers of polarized water and the restraining forces exerted by the salt linkages and H-bonds. Taking into account also the different structure-breaking effects of different salts, theoretical curves can be constructed which describe the complex multiple peak-plateau of swelling curve observed in frog muscle in response to increasing concentrations of different chloride salts.

Notes: [Auszug] SIR-It is disturbing that you should publish such a prejudiced review (Nature 320, 318; 1986) of Sonny Kleinfield's book, A Machine Called Indomitable, containing derogatory remarks about Raymond Damadian, whose struggles have given the world a powerful tool for medical diagnosis. The reference to ...

Notes: Summary In this article, the key concepts of the association-induction hypothesis and their experimental verifications were reviewed: According to this hypothesis, the bulk of cell water exists in the state of multilayers polarized and oriented by the backbones of certain proteins existing in an extended state. The major intracellular cation, K+, is also adsorbed but singly and on different protein sites (i.e.,β &γ-carboxyl groups). The living protoplasm of protein, ion and water represents a three-dimensional cooperative assembly under the control of certain cardinal adsorbents, of which ATP is a prime example. Association of ATP with the cardinal site of a key protein may produce a cooperative change in the electron distribution of the protein with consequent change of the state of ion and water adsorption. Such an alteration in the physical state of water leads to a change in the solubility of various solutes in this water as well as permeability of various solutes (e.g., Na) through this water. In contrast to the conventional concept, the role of ATP is not to provide a package of energy held in a special chemical bond. Rather, as a cardinal adsorbent, ATP acts by means of its specific electronic interaction with the protein molecules, maintaining the protein—ion—water system at a higher energy state. Dephosphorylation of ATP leads to a cooperative shift of the electron state of the whole assembly to a lower energy state. Restoration to the original resting state follows the resynthesis of ATP (where energy is injected into the system) and its readsorption on the cardinal site. Living cells typically reside in a liquid environment. The discontinuity of the cell interior from the external milieu, essential for the normal functioning of the living cell, has long been a subject of central interest in mechanistic biology. Prominent in this discontinuity is the much higher concentration of K+ and much lower concentration of Na+ in the cell interior than in the cell environment, seen in virtually all living cells. We shall begin the present article with a discussion of the subject.

Notes: 1. The effluxes of labeled Na+, D-arabinose, and sucrose from normal muscle and muscle poisoned with low concentrations of iodoacetate were studied. The procedure involved repeated loading with isotope, followed by washing of the same muscle while still normal and at different states of dying. 2. The rates of Na+ efflux in both the fast and slow fraction remained either quite constant or showed some unpredictable, minor fluctuations. This was true for both Na+ and the two sugars studied, confirming earlier conclusions that the steady levels of these solutes were not maintained by pumps. 3. In all cases studied, the efflux curves showed at least two fractions. It is the fast-exchanging fraction that steadily and consistently increased in magnitude as the muscles were dying, until finally the concentration of solute in this fraction reached and sometimes surpassed the labeled solute concentrations in the original labeled solutions in which the muscles were equilibrated. The slow fractions showed only a transient increase or none at all. These observations show that it is the fast fraction that represents solute dissolved in cell water and rate-limited by passage through the cell surface and that the partial exclusion of Na+ and the sugars have a unitary cause - a reduced solubility in the cell water which in the presence of ATP exists in the state of polarized multilayers.

Notes: 1We studied the equilibrium distribution of Mg++ in the form of chloride and sulfate at two temperatures (5° and 25°C) in frog voluntary muscles. External Mg++ concentration was varied between 1.2 and 73.2 mM with the specific purpose of testing the diametrically opposed predictions of the membrane theory and the association-induction hypothesis.2There was a linear gain of Mg++ over the entire range of external Mg++ concentrations studied at both 5°C and 25°C. In a plot of intracellular Mg++ concentration in μmoles per gram of fresh muscle cells against extracellular Mg++ concentration, the slopes observed were 0.220 at 5°C and 0.0206 at 25°C.3The increase of external Mg++ from 1.2-73.2 mM at constant external K+ concentration (2.5 mM) had no discernible effect on intracellular K+ concentration, which remained constant at its normal levels in the vicinity of 90 μmoles/g/ fresh muscle cells.4We observed a similar rectilinear distribution of Mg++ in frog ovarian eggs. As in muscle tissues, no major alteration of intracellular K+ concentration results from increases of external Mg++ concentration from 1.2-73.2 mM.5With the rectilinear gain of Mg++, there was an entirely parallel gain of chloride in frog muscle cells. Indeed the slope of the Cl- curve and that of the Mg++ curve have essentially the same value. Thus Mg++ has entered the cell accompanied by chloride (and sulfate), rather than by exchange with other intracellular cations.6An increase of external K+ from 2.5 mM to 100 mM at a constant external Mg++ concentration depolarizes the muscle cell resting potential as shown by Ling and Gerard, ('50) and causes an increase of intracellular K+, doubling its normal concentration to 200 μmoles/g fresh muscle cells. Notwithstanding, the intracellular concentration of Mg++ remained totally unchanged from its normal value.7These findings profoundly disagree with the predictions of the Donnan theory of membrane equilibrium, according to which profound alteration of intracellular K+ concentration should follow exposure to high external Mg++ concentration, and vice versa. Furthermore, the postulation of a Mg++ pump is not feasible not only because of its energy requirements, but because it would also be inadequate to explain the lack of effect of varying external Mg++ concentration on the resting potential, the intracellular K+ concentrations, as well as the pattern of Cl- uptake totally different from that predicted by the membrane theory.8On the other hand, Mg++, K+, and Cl- distributions correlated completely with the predictions of the association-induction hypothesis, according to which Mg++ and K+, in a normal resting cell, are predominantly adsorbed on sites they do not share, hence there is no mutual interference. Saturating all the intracellular sites at an external concentration of 1.2 mM, the concentration of Mg++ in the muscle cells increased further only in the form of free Mg++ (accompanied by its anion) in the cell water.9The q-value for Mg++ in muscle cells at two different temperatures permits calculation of the thermodynamic parameters of the distribution of Mg++ salt in frog muscle cell water: a moderately favorable ΔH equal to -0.516 Kcal/mole, and an unfavorable entropy of 4.37 cal/degree/mole, showing an entropic cause for the exclusion of Mg++ from cell water.