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PubMed1979

Preferential affinity of high molecular weight high mobility group non-histone chromatin proteins for single-stranded DNA.

We have subjected proteins dissociated from chicken erythrocyte or calf thymus chromatin by 0.35 M NaCl to sequential chromatography on columns containing immobilized double-stranded DNA and single-stranded DNA. At 0.2 M NaCl, 1 mM Tris . Cl (pH 7.5), the high molecular weight, high mobility group proteins (HMG-1, HMG-2, and HMG-E), were not retained by double-stranded DNA columns, but were retained by single-stranded DNA columns. Thus, in that solvent, those proteins exhibit selective affinity for single-stranded DNA. This suggests that the functions of the high molecular weight, high mobility group proteins might involve destabilizing the DNA double helix by virtue of their preferential affinity for single-stranded DNA.

Amino Acids↗
PubMed1977

Heterogeneity in electrophoretic mobility and in molecular size of lactate dehydrogenase-immunoglobulin G complexes.

Some human sera have been found to contain lactate dehydrogenase (LDH)-immunoglobulin complexes. A serum with LDH-IgG3 complexes was further analysed. Complexes with different net charge and different molecular size were found. Their isoelectric points, measured by isoelectric focusing, were in the range of pH 6.3 to 7.2. Gel-filtration experiments showed that the molecular size varied from about 300 000 to 1 000 000. Most of the complexes could be precipitated from solution with 30--40% saturated ammonium sulfate or a low ionic strength.

Antigen-Antibody Complex↗
PubMed1979

Electrophoretic mobility of high-molecular-weight, double-stranded DNA on agarose gels.

A new theoretical model for the migration of high-molecular-weight, double-stranded DNA on agarose gels is presented. This leads to the prediction that under certain conditions of electrophoresis, a linear relationship will exist between the molecular weight of a DNA molecule, raised to the (-2/3) power, and its electrophoretic mobility. Agarose gel electrophoresis of the fragments of bacteriophage lambda DNA produced by several restriction endonucleases confirms this relationship, and establishes some of the limits on its linearity. For this work, a polyacrylamide slab gel apparatus was modified for use with agarose gels. This apparatus has several advantages over others commercially available for agarose gel electrophoresis, including the abilities to run a larger number of samples at one time, to use lower-concentration gels, and to maintain better temperature stability across the width of the gel. The validation of the relationship developed here between molecular weight and electrophoretic mobility should make this a useful method for determining the molecular weights of DNA fragments.

DNA↗
PubMed1975

Conversion of human erythrocyte-adenosine deaminase activity to different tissue-specific isozymes. Evidence for a common catalytic unit.

Adenosine deaminase activity resides in various characteristic isozymes in red blood cells (RBC-ADA) and other tissues. Absence of RBC-ADA has been reported in a proportion of patients with autosomally inherited severe combined immunodeficiency (SCID). We have previously reported that the tissue isozymes of ADA are also deficient in children with SCID and RBC-ADA deficiency, although these isozymes differ from RBC-ADA in molecular weight, accessible SH groups, and electrophoretic mobility. The deficiency of all types of ADA in SCID implies that a catalytic unit of ADA in each isozyme is coded by the same structural gene. The relationship of RBC-ADA and the different tissue ADA isozymes is the subject of this paper. Incubation of RBC-ADA with ADA-deficient liver, kidney, and fibroblast extracts resulted in the appearance of new isozymes of ADA. These newly generated isozymes had the physicochemical and electrophoretic characteristics of the tissue-specific isozymes obtained from normal tissues. The electrophoretic mobility of the isozyme generated appeared to depend upon the tissue utilized and corresponded to the electrophoretic mobilities of the ADA isozymes found naturally in each of the different tissues. Additionally, the genetically determined polymorphism exhibited by RBC-ADA could be detected in the isozyme generated. Incubation with normal kidney also caused conversion of the RBC isozyme to the kidney form. These findings further support the concept that the catalytic activity of each of the several forms of the ADA enzyme resides in a single molecule coded at the same genetic locus as is defective in one form of SCID. The tissue-specific isozymes, which differ in electrophoretic mobility and molecular weight, are generated by interaction of the RBC catalytic unit with tissue-specific factors present in the different tissues of normal humans and patients.

Aminohydrolases↗
PubMed1976

Further purification and characterization of serum proteins used to detect cystic fibrosis genotypes by isoelectric focusing.

Sera from cystic fibrosis (CF) homozygotes and obligate heterozygotes contain a CF factor (gamma CF factor) not found by isoelectric focusing in thin-layer polyacrylamide gels in most normal control sera. In addition, sera from most obligate heterozygotes lack another protein (bland B, C, or D) that is commonly found in sera from most normal and cystic fibrosis individuals. A standardized, biophysical assay is described that employs isoelectric focusing for the detection of both CF homozygotes and heterozygotes based on the analysis of whole serum for the presence of the gamma CF factor and bands B, C, and D. Results of analyzing sera from selected CF patients by isoelectric focusing indicated that there is a general correlation between the amount of the gamma CF factor and the clinical severity of the disease. Partial purification and characterization of the gamma CF factor and protein bands B, C, and D was accomplished by using DEAE-cellulose chromatography, Sephadex G-200 gel filtration, sequential molecular filtration through a series of Amicon Diaflo ultrafiltration membranes, affinity chromatography, and cellulose acetate electrophoresis. The gamma CF factor is a cationic protein with a pI of 8.46+/-0.05, has gamma electrophoretic mobility, a molecular weight between 3,500 and 10,000, and apparently exists in CF serum in 2 forms (free in solution and complexed to IgG). Bands B, C, and D are cationic proteins with pI values of 7.85 to 8.10, have gamma electrophoretic mobility and a molecular weight of approximately 100,000-150,000.

Adolescent↗
PubMed1979

Purification and properties of prothrombin modified by asbestos filtration of human plasma.

Filtration through asbestos filter (Seitz) of human plasma modified the prothrombin molecule as previously shown. Factor II could no longer be activated by physiological activators (Ca++ + phospholipid + V and Xa) but reacted readily with staphylocoagulase. The separation and purification of the modified prothrombin allowed allowed the preparation of two fractions: A small slightly modified accessory fraction, "prothrombin-asbestos-1", lost its ability to be activated by physiological activators, and its ability to be adsorbed by barium citrate, but retained the immunological reactivity of fragment 1, as well as the mobility and molecular weight of unmodified prothrombin. A main fraction, "prothrombin-asbestos-2" appeared to be a modified prothrombin which has lost its N-terminal extremity. It was not adsorbed by barium citrate and could not be activated by physiological activators. It possessed a reduced electrophoretic mobility, as well as a reduced molecular weight (39,000), which are properties similar to those of thrombin. Both fractions 1 and 2 were devoid of thrombin activity. Asbestos was thus able to break the prothrombin molecule non enzymatically, the amputation of the N terminal extremity being responsible for the new functional and physicochemical properties of the molecule. Staphylocoagulase appeared not to need the N terminal extremity of the molecule of prothrombin to form the active thrombin-coagulase complex.

Asbestos↗
PubMedDate not supplied

Quantitation of human granulocyte protease inhibitors in non-purulent bronchial lavage fluids.

The predominant inhibitors of granulocyte proteases in plasma (alpha1-antitrypsin, alpha1-antichymotrypsin, and alpha2-macroglobulin) were quantitated in unconcentrated bronchial lavage fluids obtained from non-infected individuals, together with the acid-stable low molecular weight inhibitor with activity against granulocyte elastolytic and chymotrypsin-like enzymes. This latter inhibitor accounted for about 90% of the total molar concentration of granulocyte protease inhibitors in the bronchial lavage fluids. The remaining 10% consisted mostly of alpha1-antitrypsin and alpha1-antichymotrypsin. About 85% of the bronchial inhibitor was in a free form with preserved enzyme reactivity. The remaining 15% of the immunoreactive bronchial inhibitor exhibited a molecular size indicating complexation with enzymes. The major portion of alpha1-antitrypsin and alpha1-antichymotrypsin showed electrophoretic mobilities and molecular sizes similar to the native proteins but had no enzyme reactivity.

Adult↗
PubMed1979

Specific assay for pregnancy-specific-beta 1-glycoprotein (Sp1-beta). Preparation of antiserum specific for SP1-beta by absorption with a crossreacting high molecular weight serum protein.

Two pregnancy-associated proteins reacting with antibody against pregnancy-specific beta 1-glycoprotein (PS beta G or SP1) were separated by means of ammonium sulphate precipitation, size chromatography and preparative zone electrophoresis. The antibody preparation was made monospecific to the beta-mobile protein by liquid phase cross-absorption of anti-SP1 immunoglobulin preparation with the isolated alpha2-mobile high molecular weight protein. The specificity of the absorbed antibody was tested in line immunoelectrophoresis, rocket immunoelectrophoresis and crossed immunoelectrophoresis.

Absorption↗
PubMed1975

Polyadenylate metabolism in the nuclei and cytoplasm of Saccharomyces cerevisiae.

A procedure has been designed for the simultaneous isolation, in a single step, of the nuclei and cytoplasm of Saccharomyces cerevisiae alphas288c spheroplasts. We have examined the polyadenylate poly(A)-containing RNA in these fractions and their kinetics of synthesis. Nuclear RNA saturates with [3H] adenine within 10 min. Labeled RNA appears very quickly in the cytoplasm, exceeding the amount of labeled nuclear RNA within 2 min after the addition of [3H] adenine. Nuclear poly(A)-containing RNA is approximately 10% of the total cellular poly(A)-containing RNA obtained from spheroplasts labeled for 15 min. Nuclear poly(A)-containing RNA is not as large as the giant heterogeneous nuclear RNA of animal cells. The distribution of molecular size in nuclear and cytoplasmic populations of poly(A)-containing RNA is very broad with the average size of the nuclear species being moderately larger than the cytoplasmic species. Three distinct size classes of poly(A), with different apparent kinetic properties, are obtained from yeast poly(A)-containing RNA. Their electrophoretic mobility suggests molecular lengths of approximately 20, 40, and 60 nucleotides (Groner, G., Hynes, N., and Phillips, S. (1975) Biochemistry, 13, 5378-5383). Each of these poly(A) classes are present in the mRNA from large and small polyribosomes.

Adenine↗
PubMed1976

Partial purification and characterization of a triglyceride lipase from pig adipose tissue.

A triglyceride lipase was extracted from defatted pig adipose tissue powder with dilute ammonia and purified about 230-fold by a combination of ammonium sulfate fractionation, heparin-Sepharose 4B, DEAE-cellulose, and Sephadex G-150 column chromatographies and isoelectrofocusing electrophoresis. The enzyme was distinguishable in physical and kinetic properties from the two previously defined lipases in adipose tissue, lipoprotein lipase, and hormone-sensitive lipase. The purified enzyme was fully active in the absence of serum lipoprotein and was not stimulated by adenosine 3':5'-monophosphate-dependent protein kinase. In marked contrast to the already defined lipases, the enzyme was strongly inhibited by serum albumin. The enzyme had a molecular weigt of about 43,000, a pI of 5.2, and pH optimum of 7.0. The enzyme hydrolyzed triolein to oleic acid and glycerol, and did not exhibit esterase activity. The apparent Km for triolein was 0.05 mM. Physiological roles of this new species of lipase remained to be explored.

Adipose Tissue↗
PubMed1975

The electrophoretic mobilities of 5-dimethylaminoaphthalene-1-suphonyl-glycopeptides and their relation molecular weight.

The relationship between the electrophoretic mobility at pH2.1 of dansyl-glycopeptides of known composition and their molecular weight is shown to conform with a model equation previously derived for peptides. A dansyl-glycopeptide prepared from hen's-egg ovotransferrin is degraded sequentially with two glycosidases. The molecular weight of each glycopeptide intermediate formed is determined from its electrophoretic mobility. From successive molecular-weight changes, the number and type of sugar residues lost from the parent glycopeptide can be decided and the probable composition of each intermediate determined. The notion that the method has considerable application and would permit analysis of very small quantities of glycopeptides is discussed.

Acetylglucosaminidase↗
PubMed1978

Purification of retinol-binding protein from serum and urine by affinity chromatography.

A new method for the purification of retinol-binding protein from urine and serum is described. The method is based on the reversible binding of retinol-binding protein to retinoic acid linked to Sepharose and prealbumin linked to Sepharose. The yield is comparable to conventional methods using ion exchange and gel filtration and the product is an apo retinol-binding protein of high purity. The product has the same electrophoretic mobility and molecular weight and the same ability to interact with retinoic acid and prealbumin as retinol-binding protein prepared by conventional methods.

Chromatography, Affinity↗
PubMed1976

Partial purification of human leucocyte migration inhibitory factor (LIF) by immunosorption of supernatant protein contaminants detected by crossed immunoelectrophorsis.

Concentrated supernatants from washed human lymphocytes incubated in serum-free medium were investigated by crossed immunoelectrophoresis. Quantitatively, the most important macromolecules were serum proteins, in particular albumin and degraded products of albumin. No gross difference was detectable between supernatants from concanavalin A stimulated and unstimulated lymphocytes. The degraded proteins were considered to arise as a result of proteolytic enzymes present in both stimulated and unstimulated lymphocyte supernatants. These molecules exhibited almost the same electrophoretic mobility and molecular weight as native albumin, and might therefore be expected to be difficult to separate from some lymphokines by conventional biochemical techniques. Rabbit immunoglobulins to whole human serum proteins together with immunoglobulins against crude supernatants of mitogen stimulated lymphocytes were therefore bound covalently to an agarose matrix. This preparation efficiently removed all detectable proteins from concentrated supernatants of activated lymphocytes as determined by crossed immunoelectrophoresis. Leucocyte migration inhibitory factor (LIF) was recovered almost quantitatively, and a 40-fold purification of LIF was achieved. The technique is rapid, economical and well suited as an initial step for purification of large quantities of LIF.

Animals↗
PubMed1978

Immunogenic properties of tobacco smoke.

The immunogenic capacity of tobacco smoke or tobacco smoke in combination with host proteins to stimulate antibody production in rabbits was investigated. Several antisera from rabbits immunized with tobacco smoke components reacted by immunoprecipitation with tobacco smoke or leaf antigens. The serum precipitins were present only in immune sera and had electrophoretic mobility and molecular size identical to immunoglobulin. These results suggest that tobacco smoke contains components capable of stimulating an immune response in rabbits. It is possible that these components are immunogenic in man, although their role as allergens remains to be determined.

Allergens↗
PubMed1976

Nuclear transcripts larger than the cytoplasmic mRNAs are specified by segments of the adenovirus genome coding for early functions.

Nuclear viral RNAs synthesized early in productive infection with adenovirus 2 were analyzed by hybridization to specific viral DNA fragments. Radioactive RNAs were subjected to electrophoresis in polyacrylamide gels containing 98% formamide, and the fractionated RNA was hybridized to specific DNA fragments generated by cleavage with endo R-Eco Ri or endo R-Sma l. The viral genes expressed early in infection are located in four different segments of the genome. When nuclear RNA was hybridized to DNA fragments representing each of these segments, discrete RNA size classes were detected. For each of these four regions of the genome, some of the discrete nuclear RNAs were larger than the cytoplasmic mRNAs. As calculated from electrophoretic mobility, the molecular weight of these nuclear RNA size classes ranged from 15% to several fold greater than that of the corresponding cytoplasmic mRNAs. Hybridization-inhibition experiments were performed to analyze the sequences present in one of these larger nuclear transcripts, a 22S RNA transcribed from the left-hand end of the genome. This 22S nuclear RNA was transcribed from the same strand as the viral mRNA, for it contained cytoplasmic sequences; it also contained sequences restricted to the nucleus. The larger nuclear RNAs may serve as precursors to the cytoplasmic viral mRNAs synthesized early in infection.

Adenoviridae↗