PubMed Health⌕ Search

Biomedical subjects

J S Baumstark

Publications and source records attributed to J S Baumstark.

4 recordsLinked to original sources
PubMed1978

Quantitative immunofixation of proteins following zone electrophoresis in agarose gel: application to the determination of the stoichiometry of the alpha1-antitrypsin-elastase interaction.

A method for the quantitative determination of proteins by immunofixation-agarose gel electrophoresis is described. The proteins are separated electrophoretically and the resulting circular zone overlaid with specific antibody-impregnated filter paper (10.2 microliter/cm2). Following incubation for 20 h at room temperature the plates were processed, stained and the areas of the precipitin zones determined by planimetry. Intra-plate variation (coefficient of variation) for alpha1-antitrypsin (30 samples) and elastase (30 samples) at concentrations of 0.25, 0.5 and 1.0 mg/ml was 2.2--5.8% and inter-plate variation ranged from 2.9% to 5.2%. Overall, the analyses showed that the method is the statistical equivalent of rocket immunoelectrophoresis. The lowest concentration used was 0.25 mg/ml which corresponds to a sensitivity of 1.25 microgram (5 microliter per sample well). It is conceivable that lower amounts could be successfully determined. Application of the method to the determination of stoichiometry of the alpha1-antitrypsin--elastase interaction permitted the simultaneous quantitative determination of inactivated alpha1-antitrypsin (an acidic protein) and excess elastase (a basic protein) in alpha1-antitrypsin--elastase reaction mixtures (molar ratio elastase/alpha1-antitrypsin = 1.3) and thus by difference, the amount of elastase and and alpha1-antitrypsin in the alpha-antitrypsin--elastase complex. The results showed that the molar combining ratio of inhibitor to enzyme was 1.086 : 1 or 1 : 1. Conventional inhibition experiments (residual elastase activity as a function of increasing amounts of alpha 1-antitrypsin) showed this ratio to be 1.79 : 1 but 1.03 : 1 when the inactivation reaction, as determined by quantitative immunofixation, was taken into account. The quantitative immunofixation method should be applicable to interacting systems which, like elastase and alpha1-antitrypsin, result in complexes with electrophoretic mobilities intermediate to the parent proteins.

Antibodies↗
PubMed1976

A new method for the determination of alpha1-protease inhibitor (alpha1-antitrypsin) phenotypes based on the formation of alpha1-protease inhibitor allele product-elastase complexes.

Up until now it has been assumed that the protease-binding property of alpha1-protease inhibitor (alpha1PI) was destroyed by acid starch gel electrophoresis (pH 4.9). Analyses on acid starch gel blocks for pH and conductivity changes during and following a typical electrophoretic run showed that it was unlikely that the separating alpha1PI would be exposed to pH values lower than 6.2, and that the allele products, following the passage of the buffer front, were in an environment of constant pH(6.3), extremely low conductivity and high field strength. These results strongly suggested the likelihood that alpha1-PI would be chemically and physically unchanged as a result of exposure to acid starch gel electrophoresis. In order to test this likelihood, human serum was electrophoretically separated in acid starch gel and following electrophoresis, was immersed in 0.1 M diethylbarbiturate buffer, pH 8.6, containing 20 mug/ml of pancreatic elastase. The pH-adjusted (8.15) and elastase-impregnated starch gel layer was superimposed on hemoglobin-agar for 2.5 h at 37 degrees C followed by immersion of the hemoglobin-agar layer in 1% NaCl overnight, distilled water for 2 h, drying under filter paper and staining. The results showed zones of undigested hemoglobin indicating, unequivocally, that the separated alpha1PI allele products are capable of forming complexes with proteases and that alpha1PI is not inactivated following exposure to acid starch gel electrophoresis. Densitometric analysis of the transparent stained zones on a clear agar gel background offers an alternative to analysis of the acid starch gel-separated zones by antigen-antibody crossed electrophoresis and as such is suitable for identification of alpha1-protease inhibitor phenotypes. Further, the method is specific for alpha1PI and a densitometric scan provides direct information relative to the protease-binding capacity of the sample as well as the contribution of each alpha1PI allele product to that capacity.

Alleles↗