Physiology, question functions

Mitochondrial malate dehydrogenase (MDH) from several species has been shown to exist in several enzymically active forms which also appear to be conformational isoenzymes (Kitto et al, 1966, 1970). Kitto et al (1970) showed, in contrast to Epstein and Schechter (1968), that these MDH s were interconvertible in vitro, had the same amino acid compositions and molecular weights, but differed, once reversibly denatured, considerably in their heat stability. Similar interconversion of isoenzymes has also been observed with purified preparations of horse liver alcohol dehydrogenase (Lutstorf and von Wartburg, 1969). The question arises if such conformers are of any physiological or functional significance. It is possible that beeause of their differences in surface charge, the various conformative isoenzymes are differently bound within a cell. 

The natural question is, how did such a variety of physiological and functional properties of this polysaccharide originated, despite its quite simple chemical structure To clarify this issue even partially, the authors attempted to link the biological functions of hyaluronic acid with the general principles of the structure and physicochanical properties, using a... 

The recent explosion in the discovery of new myosin genes has led to the idea that myosins from different classes probably co-exist in cells. This has raised the obvious question as to what functions these myosins subserve within cells. Up to now, only the genes have been cloned for many of the 35 unique myosins. But this is not a question that can be answered solely by cloning rather, it is absolutely imperative to biochemically characterize these proteins if we are to understand their physiological properties. One way to do this is to express the entire protein or parts of the proteins in bacteria, yeast, or insect cells, and to then purify and characterize... 

In order to answer questions regarding the therapeutic and cosmetic uses of the myriad dermatological concoctions available, a pharmacist must be knowledgeable about the anatomical structure and physiological functions of the skin and the chemical compositions and physicochemical properties of its constituent tissues. Some understanding of how its properties are affected by disease and damage is a must, as is... 

Despite a long-time studying of superoxide production by mitochondria, an important question is still debated does mitochondria produce superoxide under physiological conditions or superoxide release is always a characteristic of some pathophysiological disorders resulting in the damage of normal mitochondrial functions Uncertainties in this question arise due to the different results obtained with the use of respiratory inhibitors and different analytical methods. 

The existence of two distinct functions within the one membrane protein raises a number of interesting questions about transporter functions, such as what is the relative importance of the two functions Can they be allosterically regulated under physiological conditions or manipulated by pharmacological methods What is the structural basis for the dual functions In the next section, we shall attempt to address some of these issues and also to present some of the current understanding of the structural basis for these functional states. 

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