Studies on Blood Group A Substance

Citation

Holzman, George (1948) Studies on Blood Group A Substance. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/c6fv-2w05. https://resolver.caltech.edu/CaltechTHESIS:05302025-184553880

Abstract

A study has been made of the isolation of blood group A-substance from various sources with the aim of ascertaining the relative efficacy of procedures in concentrating A-substance. Preparations of A-substance were isolated from hog gastric mucin, hog gastric mucose, pepsin, human erythrocytes and stromata, and pseudomucinous ovarian cyst fluids according to procedures previously described. This has afforded a direct comparison of the procedures and products obtained.

In order to facilitate the examination of the activities of fractions obtained in isolation procedures, a color test was developed which under certain conditions can be used to predict serological potencies. The carbazole reaction for the estimation of hexoses in polysaccharides was also reinvestigated and an improved procedure developed.

The preparation of A-substance from hog mucin was studied in detail by means of electrodialysis and alcohol fractionation and with the aid of a number of criteria of fractionation including serological potency, elementary analyses, analyses for a few sugars and amino acids, and ultraviolet absorption spectra. Spectrophotometric analyses have also led to the separation of highly potent, electrophoretically homogeneous, preparations into two distinct fractions differing strikingly in their solubility at low ionic strength and low pH. The more active insoluble component was inhomogeneous, however, by electrophoresis, solubility, particle size studies, and serological specificity.

A preliminary investigation of the nature of the alkaline decomposition of A-substance and of some of the products so formed was made.

The diurnal variation in the carbon dioxide content of the extractable gases of leaves of Bryophyllum fedtschenkoi was measured; results were not decisive in testing a hypothesis concerning the mechanism of diurnal acid production of succulents.

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