Comparative physiology definition

Although ancients and moderns alike have called attention to variability and individuality as factors particularly related to disease susceptibility and moderns have recognized that variability is indispensable to evolution, comparatively little research time and effort have been devoted to definitive study in physiology and biochemistry as to precisely how so-called normal individuals differ from each other. Such study necessarily involves repeated observations on the same individuals, in contrast to a series of single observations on representative populations. No attempt to bring together the available biochemical material on normal variation has been previously made so far as I know. 

ILLUSTRATIVE EXAMPLE 11.15 A chemical engineering student decided to model the human stomach as a reactor vessel. After studying anatomical and physiological data, the student was unsure whether to model the stomach as a CSTR or a batch reactor. To reach a definitive conclusion, he took representative data (see parameters given below) and decided to calculate the residence time for both a batch reactor and a CSTR, and compare these data to the biological information he obtained. 

Conversion of the proenzyme into its active form. We concluded that only the proenzyme form of acid protease can exist in human seminal plasma at the physiological pH of around 7.5 therefore, we investigated activation of proenzyme in acid medium. The purified proenzyme was incubated in 1 mM HCl, pH 3, for 1 hr, and then chromatographed on Sephadex G-50 column. The proenzyme was converted into an active form and some peptide of small molecular weight was released (Fig.2). As shown in Table II, when the amino acid analyses of the proenzyme, the active form, and activation peptide were carried out, the number of each amino acid residue of the proenzyme agreed well with the additive value between the number of that amino acid in the active form and activation peptide. This supported the conversion of the proenzyme to an active form. The amino acid composition of the active protease and of the proenzyme were comparable to those of bovine pepsin (10) and pepsinogen (11). However, definite differences are present. About forty residues which carried most of the basic amino acids, were released from pepsin, while sixty-nine residues, which carried about 30% of basic amino acid of the precursor were liberated from the proenzyme of seminal plasma acid protease. 

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