Robert B. Pennell

Preparation and Properties of Serum and Plasma Proteins, XXXV

Advantage has been taken of the altered solubilities of the zinc complexes of plasma proteins in developing a new system of fractionation. Zinc complexes are readily and reversibly formed; they exhibit generally reduced solubility in the neutral pH range, thus obviating exposure of the proteins to harsh conditions of pH, ionic and dielectric strengths. Many zinc protein complexes can be separated without the use of ethanol; the most soluble ones are precipitated from 15% ethanol at neutral pH. A key step involves separation of the proteins whose zinc complexes are water soluble at neutral pH from those which are insoluble. The latter fraction comprises mostly high molecular weight globulins. The water soluble fraction consists mainly of albumin and certain α‐ and β‐pseudoglobulins; it has been called Stable Plasma Protein Solution in view of its properties following zinc removal. The zinc is removed from each fraction by chelation, ion exchange, or a combination of the two. Quantitative data document the separations achieved by this new system of fractionation.

Fractionation and Isolation of Purified Components by Precipitation Methods

Publisher Summary This chapter presents sufficient background to the theory of separation of proteins from one another by precipitation techniques to permit valid assessment of what may be expected from a given technique. It describes the precipitation techniques. Separation of plasma constituents from one another is an exercise in understanding the unique characteristics of the constituents and of manipulating these characteristics in such a way that a particular component or group of components can be removed from its environment. Most such separations are performed for one of two purposes: (1) the desire to isolate, characterize, and understand the nature and function of the component, or (2) the desire to obtain the component for use in the laboratory or in the clinic.

Effect of Nitrogen Mustard on Virus of Serum Hepatitis in Whole Blood.

Summary 1. Nitrogen mustard in a concentration of 500 mg per 1 failed to inactivate the Fort Bragg strain of serum hepatitis virus in whole blood. 2. Possible reasons for this failure are discussed. 3. The virus titer of the whole blood used was found to be at least 25000 infectious units/ml.

Macromolecular Growth Requirements of Human Cells in Continuous Culture

Summary The essential growth factors associated with serum proteins are present in cold ethanol fraction IV-4 for most human serum pools and in fraction II + III for 2 individual equine serums. Cytotoxic activity has been found in fraction II + III from most human serum pools. Further subfractionation of IV-4 and II + III by the established cold ethanol methods fails to yield active subfractions. The significance of this finding is discussed.

Preparation of Hemoglobin Solutions Containing Hemoglobin Reducing Enzymes

Summary Hemoglobin solutions were prepared from erythrocytes that were laked in the presence of nicotinic acid amide, glucose, and ammonia. The solutions were Seitz-filtered, yielding clear solutions free from cellular debris, and containing sufficient of the enzyme systems of the cell to change the pigment from oxyhemoglobin to reduced hemoglobin with no appreciable accumulation of methemoglobin during the process. The solutions could be stored in the reduced state for protracted periods at elevated temperatures without increase in methemoglobin content.

Distribution and Partial Purification of Pituitary Gonadotropins of Human Plasma.

Summary The location and approximate concentration of gonadotropic activity in various fractions of human postmenopausal plasma has been determined. The plasma was fractionated by means of the cold ethanol method VI of Cohn and was assayed in immature female rats by estimating ovarian growth and secretory activity. Although traces of activity were found in Fractions IV-1, IV-4 and V, the bulk of the gonadotropically-active material was located in Fraction II + III. Subfractionation of Fraction II + III by successive precipitations with zinc and 20% ethanol freed the gonadotropins from the majority of the contaminating proteins.

Studies of Blood Components

Previous studies from this laboratory have shown that injection of partially purified adipose tissue extracts (ATE) can produce a significant decline in the blood glucose concentrations of adrenalectomized rats and spontaneously diabetic mice of the KK strain [l, 21. These effects were produced with either bovine or rat ATE. Partially purified ATE preparations have been obtained by a n ethanol-acetone precipitation technique [2] yielding about 30 mg of partially purified ATE per kg of bovine perirenal adipose tissue. Characterization studies, now in progress, indicate that the