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Variability of hematocrit value, blood serum beta- and gamma-globulin level and body weight in different transferrin genotypes of common vole (Microtus arvalis, Pallas 1779) from natural population.

1. Heterozygotes TfF/TfE of voles did not differ in body weight, they had higher hematocrit value (males and females), higher beta-globulin fraction (males) or higher gamma-globulin fraction (females). 2. A smaller variability of parameters studied was observed in heterozygotes than in homozygotes. Small and similar variability occurred in hematocrit value and beta-globulins while higher variability occurred in body weight and gamma-globulins. 3. In common voles the faster migrating E system of transferrin may have a higher capacity for iron transport than the F system. 4. Seasonal changes of hematocrit value in vole populations seems to result from genetical and physiological variability. 5. Sexual and seasonal changes in beta-globulin level appear to be related to changes in sexual activity of the animals during the seasons. 6. In autumn, low weight of animals and high serum gamma-globulin level, with the same physiological variability of these two parameters, suggest the synthesis of gamma-globulins with tissue (muscle) proteins. 7. Autumnal increase of gamma-globulin level seems to be very important, taking into consideration the role of the protein in water retention and its filtration from the tissues. Very high level of the protein fraction may play a role in winter high mortality of voles.

Animals↗

Interaction of the rheumatoid factor with antigen-antibody complexes and aggregated gamma globulin.

The effect of highly purified rheumatoid factor on the precipitin reactions of various antigen-antibody systems was determined. The amount of nitrogen precipitated was increased over a broad range when the factor was added to ovalbumin, human albumin, or human gamma globulin, and the corresponding rabbit antibodies. In the zone of antigen excess, soluble antigen-antibody complexes were precipitated by rheumatoid factor. Soluble aggregates of human and rabbit gamma globulin, produced by heating at 63 degrees C., treatment with urea plus mercaptoethanol or treatment with guanidine, also precipitated with rheumatoid factor. Ultracentrifugal analysis of dissolved specific precipitates showed the presence of aggregated gamma globulin. The sedimentation rate of reactive aggregates was greater than 20 S, and concentrated preparations free of the non-reactive 7 S gamma globulin could be prepared by various procedures of zone centrifugation. These aggregates showed a high inhibitory capacity in the sensitized sheep cell agglutination reaction. Solid gamma globulin, prepared by heat denaturation, also selectively adsorbed the rheumatoid factor, and removed or decreased the activity in the various precipitation and agglutination reactions. Elution of highly purified active preparations from the solid gamma globulin could be carried out with urea or acid buffers. Evidence for interaction between rheumatoid factor and low molecular weight gamma globulin without precipitation, was also obtained. This interaction appears to occur in the circulation of patients with rheumatoid arthritis. The question of whether the rheumatoid factor represents an antibody to gamma globulin was discussed. Points of similarity to the behavior of complement also were cited.

Animals↗

Characterization of the reactant (gamma globulin factor) in the F II precipitin reaction and the F II tanned sheep cell agglutination test.

The material in gamma globulin ("reactant") which reacts with rheumatoid sera in the F II precipitin and F II tanned sheep cell agglutination tests was concentrated by precipitation with sodium sulfate. The concentrated "reactant" appeared to consist of polydispersed molecular aggregates of gamma globulin with s(20) constants as high as 40, as well as the previously described inhomogeneous aggregated material. Aggregated gamma globulin precipitated readily with most rheumatoid sera regardless of the reaction volume, and in low concentration inhibited the F II tanned sheep cell agglutination reaction and sensitized tanned erythrocytes to the agglutinating action of a positive rheumatoid serum. On the other hand, non-aggregated gamma globulin (7S) did not precipitate with rheumatoid sera and in low concentration did not inhibit the F II tanned sheep cell agglutination reaction, or sensitize tanned erythrocytes. Non-aggregated gamma globulin in large excess inhibited the precipitin reaction of aggregated gamma globulin with "rheumatoid factor," and accounted for the characteristic shape of the whole F II precipitin curves and the volume effect described by Vaughan (relation of increased precipitate yield relative to the reaction volume in whole F II precipitin studies). In serological systems other than the F II tanned sheep cell and F II precipitin reactions, the sensitization involves an antigen-antibody combination; i.e., sheep erythrocyte plus hemolysin in the sensitized sheep cell test, and egg albumin plus anti egg albumin in the absorption experiments with specific precipitates. The aggregation of gamma globulin that was essential for sensitization in the F II tanned sheep cell and F II precipitin tests may have simulated the aggregation of antibody gamma globulin that occurs with antigen-antibody union. The present information has been incorporated into a schematic hypothesis for the basis of the rheumatoid serological reactions.

Agglutination Tests↗

High-density lipoproteins contribute to the alpha-1-globulin zone in capillary electrophoresis of human serum proteins.

Alpha-1-antitrypsin (AAT) and alpha-1-acid glycoprotein (AAG) are reported to be the main proteins contributing to the alpha-1-globulin capillary zone electrophoresis (CZE) zone, but the sum (AAT + AAG) showed lower than the alpha-1-globulin. We investigated the role of high-density lipoprotein (HDL), an additional protein migrating in the alpha-1-globulin zone, as a possible cause for such a gap. In a set of 98 sera we measured the alpha-1-globulin with a dedicated clinical capillary electrophoresis system, and AAT, AAG and apolipoprotein A-1 (ApoA) by immunonephelometry. The alpha-1-globulin were consistently higher than the sum (AAT + AAG), by (mean value +/- standard deviation) 1.70 +/- 0.88 g/L in 49 sera with low ApoA, and by 3.59 +/- 0.75 g/L in 49 sera with high ApoA. Corresponding figures in the comparison alpha-1-globulin/(AAT + AAG + ApoA) were reduced to 1.08 +/- 0.77 g/L and 1.67 +/- 0.70 g/L. It is concluded that HDL significantly contribute to the CZE alpha-1-globulin zone, but do not completely explain the differences between the electrophoretic and the immunochemical measurements. However, CZE alpha-1-globulin measurements give information about increases of the two major acute phase proteins comparable to specific protein measurements.

Alpha-Globulins↗

2-sec-butyl-4,5-dihydrothiazole is a ligand for mouse urinary protein and rat alpha 2u-globulin: physiological and toxicological relevance.

Mouse urinary protein (MUP) and alpha 2u-globulin are structurally homologous proteins that belong to a superfamily of ligand-binding proteins and represent the major urinary proteins excreted by adult male mice and rats, respectively. Although a variety of xenobiotics bind to alpha 2u-globulin and produce a male rat-specific hyaline droplet nephropathy, no endogenous ligand for this protein has been identified. Despite extensive sequence homology. MUP does not bind to hyaline droplet-inducing agents. While performing experiments with purified MUP, we observed that it presented with a strong, distinctive odor reminiscent of mouse urine. To determine whether this odor was the result of contamination or degradation or was attributed to an endogenous ligand bound to the protein, the protein was subjected to thermal desorption and any released volatile compounds were detected with a gas chromatograph equipped with an external sniff port and mass spectrometer. With this approach, two odorous compounds were detected at the sniff port by a human observer, but only one was present in sufficient mass to allow identification. This compound, which presented with the characteristic odor, was subsequently identified as 2-sec butyl-4,5-dihydrothiazole (DHT) by GC/MS/matrix isolation IR and NMR analyses. The identification of DHT was confirmed by comparing the chromatographic and spectral properties to those of the synthesized authentic compound. In direct contrast, purified urinary alpha 2u-globulin did not present with an obvious odor, and no volatile ligands were detected on this protein. Although DHT is a major endogenous ligand for MUP, it was also found to competitively inhibit the binding of [14C]d-limonene-1,2-epoxide to alpha 2u-globulin with relatively high affinity (Ki = 2.3 microM). When dosed orally to F344 rats, DHT (1 mmol/kg for 3 days) caused the characteristic exacerbation of hyaline droplets in male rat kidneys and increased renal levels of immunoreactive alpha 2u-globulin about threefold over control levels. These results indicate that despite structural homology, MUP and alpha 2u-globulin are distinguished by the presence of a volatile endogenous ligand only on the former, a distinction that may reflect differences in the physiological functions of the two proteins. Furthermore, although DHT can bind to both MUP and alpha 2u-globulin, renal toxicity was only observed in rats, thereby emphasizing the unique toxicological properties of alpha 2u-globulin in the development of hyaline droplet nephropathy.

Alpha-Globulins↗

Barley embryo globulin 1 gene, Beg1: characterization of cDNA, chromosome mapping and regulation of expression.

We report identification of a 2189 bp cDNA clone from barley corresponding to a single-copy gene, Beg1 (Barley embryo globulin), on chromosome 4, which encodes a storage globulin. In barley, the major protein reserve in the aleurone layer belongs to the 7S globulin class of proteins found in many seeds. Electrophoretically and antigenically similar proteins are present in the barley embryo. Accumulation of Beg1 mRNA was noted beginning 15-20 days post-anthesis in both the aleurone layer and embryo of the developing barley grain but not in the starchy endosperm. A high level of Beg1 mRNA is also present in the mature imbibed aleurones, which can be repressed by treatment with gibberellic acid. This repressive effect of gibberellin on the levels of Beg1 mRNA is confirmed in the gibberellin response-constitutive mutant, slender, whose aleurone layers do not accumulate Beg1 mRNA even in the absence of applied gibberellic acid. The deduced primary translation product of the Beg1 mRNA is a 63.7 amino acid (72 kDa) protein with homology to maize embryo globulin 1 (GLB1) and a partial sequence of a wheat 7S globulin. The internal amino acid sequence of BEG1 closely matches the N-terminal sequence of isolated barley aleurone globulin. Seven imperfect tandem repeats of 16 amino acids each are present near the N-terminus of BEG1, which conform to the consensus HGEGEREEEXGRGRGR, and contribute to the observed unusual amino acid composition of this protein. A second, distinct barley globulin gene, Beg2, which is homologous to maize Glb2, was detected by Northern and Southern analysis. Beg2 and Beg1 are regulated differently which may indicate variation in storage or utilization properties among the barley globulins.

Abscisic Acid↗

Genomic organization of the rat alpha 2u-globulin gene cluster.

The alpha 2u-globulin are a group of similar proteins, belonging to the lipocalin superfamily of proteins, that are synthesized in a subset of secretory tissues in rats. The many alpha 2u-globulin isoforms are encoded by a multigene family that exhibits extensive homology. Despite a high degree of sequence identity, individual family members show diverse expression patterns involving complex hormonal, tissue-specific, and developmental regulation. Analysis suggests that there are approximately 20 alpha 2u-globulin genes in the rat genome. We have used fluorescence in situ hybridization (FISH) to show that the alpha 2u-globulin genes are clustered at a single site on rat Chromosome (Chr) 5 (5q22-24). Southern blots of rat genomic DNA separated by pulsed field gel electrophoresis indicated that the alpha 2u-globulin genes are contained on two NruI fragments with a total size of 880 kbp. Analysis of three P1 clones containing alpha 2u-globulin genes indicated that the alpha 2u-globulin genes are tandemly arranged in a head-to-tail fashion. The organization of the alpha 2u-globulin genes in the rat as a tandem array of single genes differs from the homologous major urinary protein genes in the mouse, which are organized as tandem arrays of divergently oriented gene pairs. The structure of these gene clusters may have consequences for the proposed function, as a pheromone transporter, for the protein products encoded by these genes.

Alpha-Globulins↗

Interaction of plasma proteins with cytochromes P450 mediated metabolic reactions: inhibition by human serum albumin and alpha-globulins of the debrisoquine 4-hydroxylation (CYP2D) in liver microsomes of human, hamster and rat.

The effect of human serum albumin (HSA), alpha1-acid glycoprotein (alpha1-AGP), and alpha- and gamma-globulins on the in vitro metabolism of debrisoquine in human, hamster and rat liver microsomes was studied. Interaction of albumin with cytochrome P450 mediated phenytoin metabolism has been reported. Since plasma protein binding of phenytoin is high, in the present study a weakly protein bound drug, debrisoquine, was studied. Debrisoquine is a substrate of CYP2D6. The debrisoquine 4-hydroxylation was measured using a radio-TLC method. Among the four plasma proteins, alpha-globulins had the strongest inhibitory effect on the debrisoquine 4-hydroxylase activity. The inhibition with 2% alpha-globulins was 42+/-18% for human and higher for hamster and rat liver microsomes (65-71%). HSA had less effect than alpha-globulins. In the presence of HSA, the decrease in activity was between 18 and 35% for all liver microsomes studied. The debrisoquine 4-hydroxylase activity was not significantly changed by alpha1-AGP or gamma-globulins. Using an ultra-filtration method, the protein binding of debrisoquine to 4% HSA, 0.5% alpha1-AGP, 2% alpha-globulins and 2% gamma-globulins was found to be 22, 20, 22 and 5%, respectively. Since the observed inhibition is inconsistent with level of protein binding, it appears, particularly in the case of alpha-globulins, that the plasma proteins interact with CYP2D directly.

Adrenergic Agents↗

Transcription of the alpha2u-globulin gene in male rat liver nuclei in vitro.

Alpha2u-globulin is a male rat liver protein under multihormonal control which represents approximately 1% of hepatic protein synthesis. We have measured the rate of transcription of the alpha2u-globulin gene using a nuclear cell-free transcriptional system with mercurated CTP as substrate for the endogenous RNA polymerases. The newly synthesized, mercurated RNA was purified free of endogenous RNA by chromatography on sulfhydryl agarose and hybridized to 3H-labeled alpha2u-globulin cDNA. It was found that, in male rat liver nuclei, alpha2u-globulin RNA sequences represent 0.005% of the total newly synthesized RNA. Actinomycin D or alpha-amanitin completely blocks the synthesis of alpha2u-globulin RNA in these nuclei. No alpha2u-globulin RNA synthesis was detectable in female rat liver nuclei. Thus, within the limits of our detection the absence of hepatic alpha2u-globulin mRNA in female rats appears to be due to a lack of transcription of the alpha2u-globulin gene in these animals.

Alpha-Globulins↗

Mungbean [Vigna radiata (L.) Wilczek] globulins: purification and characterization.

Vicilin type (8S) and basic 7S globulins and legumin type (11S) globulins were isolated from mungbean [Vigna radiata (L.) Wilczek]. The native molecular weights of the different globulin types were 360000 for legumin, 200000 for vicilin, and 135000 for basic 7S. Some of the 8S globulin apparently complexed and coeluted with the 11S on gel filtration. On SDS-PAGE, 11S was composed of two bands of 40000 and 24000, 8S was composed of 60000, 48000, 32000, and 26000 bands, and basic 7S was composed of 28000 and 16000 bands. The percent composition of total globulins was estimated to be as follow: 8S, 89%; basic 7S, 3.4%; and 11S, 7.6%. The basic 7S and 11S but not the 8S globulins were found to have disulfide bonds. The presence of carbohydrates by conjugated peroxidase reaction was observed in all bands of 8S, the acidic polypeptide of basic 7S, and its complex but not in 11S. The 28000 basic 7S band and its 42000 complex and the first three major bands of 8S cross-reacted with antibodies to all types of soybean conglycinin subunits (alpha, alpha', and beta), whereas the fourth band cross-reacted only with the anti-beta subunit. None of the mungbean globulins cross-reacted with anti-soybean glycinin. Basic 7S was found to be easily extracted with 0.15 M NaCl, 11S was extracted with 0.35 M NaCl,and 8S was extracted over a wide range of NaCl concentrations. The N-terminal sequences of the different subunits/fragments of the globulins were determined and found to have strong homology with storage proteins of other legumes and crops.

Electrophoresis, Polyacrylamide Gel↗

Molecular cloning of 11S globulin and 2S albumin, the two major seed storage proteins in sesame.

Insoluble 11S globulin and soluble 2S albumin, conventionally termed alpha-globulin and beta-globulin, are the two major storage proteins and constitute 80-90% of total seed proteins in sesame. Two full-length cDNA clones were sequenced and deduced to encode sesame 11S globulin and 2S albumin precursors, respectively. Deduced amino acid composition reveals that 2S albumin, but not 11S globulin, is a sulfur-rich protein. Three abundant polypeptides of 50-60 kDa were resolved on SDS-PAGE when seed-purified 11S globulin was prepared in nonreducing conditions. Immunological analysis suggests that these three polypeptides are encoded by homologous genes. Immunodetection on the overexpressed protein of the 11S globulin clone in Escherichia coli indicates that this clone encodes the precursor protein of one of the three purified 11S globulin polypeptides.

Amino Acid Sequence↗

Studies on the proteolytic activity of gamma-globulin preparations.

1. The proteolytic activities of several gamma-globulin preparations were tested. These included sulphate-precipitated human and bovine preparations and human and bovine Cohn fraction II preparations as well as purified gamma-globulin preparations. Up to 14mg. of diffusible peptides and glycopeptides/g. of gamma-globulin was liberated after dialysis and up to 10mg. of peptides/g. after incubation and trichloroacetic acid precipitation, as products of the degradation process in incubated gamma-globulin. 2. in-Aminohexanoic acid and p-chloromercuribenzoic acid, as well as heating at 60 degrees for 40min., were shown to inhibit strongly these proteolytic activities. Streptokinase was shown to activate strongly the proteolytic activity of all the human preparations (sulphate-precipitated, Cohn fraction II, and purified gamma-globulin). 3. Two distinct pH optima were shown for human and bovine gamma-globulin preparations: one at pH8, the other at pH3.8 (the latter activity could be demonstrated only in the presence of cysteine). 4. Both (131)I-labelled human Cohn fraction II and bovine fibrinogen were attacked by a sulphate-precipitated preparation of gamma-globulin. Of the synthetic substrates tested toluene-p-sulphonyl-l-arginine methyl ester was hydrolysed by both the sulphate-precipitated and Cohn fraction II preparations, as was benzoyl-l-arginine amide at pH5, but only in the presence of cysteine. 5. These data are interpreted to indicate that at least two enzymes are present in gamma-globulin preparations, one being similar to the plasmin system, the other similar to cathepsin B.

Acids↗

Androgen regulated expression of the alpha 2u-globulin gene in pancreatic hepatocytes of rat.

Under a copper-deficient regimen, pancreatic cells in the adult rat can be found to undergo differentiation into hepatocytes. Pancreatic hepatocytes induced in male and female rats were examined for the expression of the androgen-inducible hepatic protein, alpha 2u-globulin. Alpha 2u-Globulin protein was demonstrable by immunoperoxidase method in all the pancreatic hepatocytes of male rats. Northern blot analysis confirmed the presence of 1.3 kb alpha 2u-globulin mRNA transcript in the pancreas of male rats with hepatocytes. Orchiectomy resulted in marked decrease of alpha 2u-globulin protein and its mRNA. Administration of dihydrotestosterone to castrated rats resulted in increased levels of alpha 2u-globulin mRNA and the amount of alpha 2u-globulin protein in the pancreatic hepatocytes. Unlike normal males, in intact and ovariectomized females alpha 2u-globulin was not detectable in pancreatic hepatocytes. These results indicate that similar to hepatic parenchymal cells pancreatic hepatocytes synthesize alpha 2u-globulin under androgenic regulation. Furthermore, unlike in liver where it is expressed predominantly in perivenular and midlobular hepatocytes, there is no localized difference in the expression of this gene in the transdifferentiated pancreatic hepatocytes.

Alpha-Globulins↗

Hepatic synthesis and urinary excretion of alpha2u-globulin by male rats: diurnal rhythm and response to fasting and refeeding.

The urine of sexually mature male rats contains a protein of hepatic origin, alpha2u-globulin, not found in the urine of immature or female rats; output of this protein is greatly reduced by fasting. We have examined the effects of feeding and of fasting for various lengths of time on urinary output and hepatic synthesis of alpha2u-globulin. Rats eating ad libitum showed diurnal rhythms of urinary alpha2u-globulin excretion reaching maxima between 2000 and 0800 hours, thus coinciding with the daily feeding period of the rat. Fasting for 12 hours extinguished this diurnal rhythm. When fasting was prolonged up to 36 hours, urinary excretion of alpha2u-globulin was reduced to very low levels. Hepatic synthesis of alpha2u-globulin under these nutritional conditions was investigated by incubating liver polyribosomes with [3H]leucine and a preparation of soluble enzymes for protein synthesis and separating the labeled alpha2u-globulin peptides by immunoprecipitation followed by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels. By this technique, it was shown that only membrane-bound ribosomes in the livers of mature male rats make this protein. Semi-quantitative measurement suggested that the proportion of liver polyribosomes synthesizing alpha2u-globulin was unchanged after 12 hours of fasting, but was reduced after 24 and 36 hours of fasting. It is proposed that the diurnal rhythm in alpha2u-globulin output in the urine represents translational control of its synthesis in the liver, whereas the more extensive reduction with prolonged fasting is partly due to a selective reduction in transcription of the messenger RNA for this protein.

Alpha-Globulins↗

Alpha 2u-globulin nephropathy and carcinogenicity following exposure to decalin (decahydronaphthalene) in F344/N rats.

Decalin (decahydronaphthalene) is a widely used industrial solvent known to cause male rat-specific alpha2u-globulin nephropathy. In this project, 13-week and two-year inhalation studies of decalin were conducted consecutively in both sexes of F344/N rats. The key objectives were to (1) characterize the 13-week toxicity of decalin in rats, with an emphasis on nephropathy in males; (2) compare the kidney concentrations of decalin, 2-decalone, and alpha2u-globulin in males over 2 to 13 weeks of decalin exposure; and (3) correlate male rat nephropathy observed in the 13-week study with renal carcinogenicity in the two-year study. F344 rats (M/F) were exposed via whole-body inhalation to 0, 25, 50, 100, 200, or 400 ppm decalin for 13 weeks. Urine was collected at weeks 2 and 6 for creatinine and decalol analyses and at week 12 for clinical urinalysis. Right kidneys were collected from male rats at weeks 2 and 6 and from both sexes at week 13, homogenates were prepared using the whole kidney, and these homogenates were analyzed for alpha2u-globulin, decalin, and 2-decalone. Left kidneys were evaluated for histopathology and cell proliferation utilizing a proliferating cell nuclear antigen technique and counting proximal renal tubular epithelial cells to determine cell labeling indices. Necropsies and histopathologic evaluations were performed at week 13. Decalin exposure caused increases in kidney weight, urinalysis parameters (protein, AST, LDH), kidney alpha2u-globulin concentration, and proximal convoluted renal tubular cell proliferation in males. These changes were accompanied by microscopic lesions (accumulation of hyaline droplets in cortical tubules, regeneration of proximal tubular epithelium, and granular casts in medullary tubules) clearly linked to alpha2u-globulin nephropathy. Both decalin and 2-decalone were related to increased alpha2u-globulin in male kidneys. Kidney concentrations of decalin, 2-decalone, and alpha2u-globulin in exposed females were negligible, while females excreted greater amounts of decalol metabolites in urine than males at weeks 2 and 6. There were no exposure-related microscopic lesions in females. For chronic exposure, F344 rats were exposed via whole-body inhalation to 0, 25, 50 (males only), 100, or 400 ppm decalin for two years. Chronic exposure induced a spectrum of nonneoplastic and neoplastic lesions in the renal cortex of males, ranging from regenerative lesions of chronic nephropathy to tubular carcinomas. Incidences of renal tubular adenoma, tubular carcinoma, combined tubular adenomas and carcinomas, cortical tubular hyperplasia, hyaline droplet accumulation, hyperplasia of pelvic epithelium, and mineralization in renal papilla were increased in exposed males compared to controls. There was a clear increase in the mean severity of chronic nephropathy in decalin-exposed males. It was concluded that the carcinogenic effect on the renal cortical epithelium of male rats exposed to decalin was related to increased turnover of this epithelium, resulting from the cytotoxic effects of alpha2u-globulin accumulation in the renal cortical tubular cell cytoplasm.

Adenoma↗

A clinical and laboratory evaluation of immune serum globulin from donors with a history of hepatitis: attempted prevention of post-transfusion hepatitis.

A controlled trial of passive immunization for prevention of post-transfusion viral hepatitis was carried out in order to determine whether effective levels of antibody were present in the "convalescent" immune serum globulin used in the study. This globulin was prepared selectively from plasma of donors giving a history of overt viral hepatitis two or more years earlier. The proportion of contributors to the globulin who had B hepatitis was unknown but the final product contained a low titer of antibody to the surface antigen of hepatitis B virus (anti-HBs). The failure of 20 ml of immune serum globulin to reduce the incidence of type B post-transfusion hepatitis (7/93) below that of placebo-treated controls (8/102) was not unexpected in view of the globulin's low titer of anti-HBs. However, more than two thirds of the post-transfusion cases were not type B and were as plentiful among globulin recipients (17/93) as among controls (17/102). Although some of the donors from whom the immune serum globulin was obtained may once have had the same type(s) of hepatitis as the non-B cases currently observed in transfusion recipients, the globulin apparently did not contain enough specific antibody to confer protection in the dose schedule tested.

Antibodies, Viral↗

Limited proteolysis of beta-conglycinin and glycinin, the 7S and 11S storage globulins from soybean [Glycine max (L.) Merr.]. Structural and evolutionary implications.

The G2 (A2B1a) glycinin subunit from soybean (Glycine max L. Merr.) was purified and renatured to the homohexameric holoprotein. This protein along with purified beta-conglycinin were subjected to limited proteolysis by trypsin. The generated polypeptide fragments were separated via SDS/PAGE and the amino acid sequence of the N-terminals was determined. Four cleavage points were detected in the alpha-chain A2 of glycinin as well as in the alpha'-chain of beta-conglycinin. From the known three-dimensional structure of 7S globulin and the hypothetical model of 7S globulin-like 11S globulin structure, it was possible to draw the conclusion that two distinct types of susceptible sites for proteolytic cleavage are characteristic of the subunits of both globulins. The first includes the sequences linking N- and C-terminal domains of both globulins and the sequence of N-terminal extensions of 70-kDa subunits from the vicilin-like 7S globulins. The second type includes the loop between beta-strands E and F of the N-terminal domain of 11S globulins and of the C-terminal domain of 7S globulins. A statistically significant similarity was found between the N-terminal extension of the alpha'-chain of beta-conglycinin and the interdomain linker regions of soybean glycinin and pea legumin. It is proposed that the three sequence regions which form the first type of susceptible sites are of similar structural function and might have evolved from the N-terminal segment of a putative single-domain ancestor.

Amino Acid Sequence↗

Studies on red cell aplasia. V. Presence of erythroblast cytotoxicity in G-globulin fraction of plasma.

The marrow cells of a patient with pure red cell aplasia markedly increased their rate of heme synthesis when they were freed from the host environment and were incubated in vitro. When the red cell aplasia was treated with cyclophosphamide and prednisone, marrow cell incorporation of (59)Fe into heme in vitro increased several weeks before a reticulocytosis was apparent, and was the earliest effect noted. The plasma gammaG-globulins of this patient inhibited heme synthesis by normal marrow cells or the patient's own marrow cells obtained after remission of the disease. Since the inhibition of heme synthesis could be the result of damage to erythroblasts, the patient's posttreatment marrow cells or normal marrow cells were labeled with (59)Fe and were then incubated with the patient's pretreatment, treatment, and posttreatment gammaG-globulins as well as normal gammaG-globulins. At the end of this incubation the supernatant and cells were separated and counted. Heme was extracted and also was counted. Treatment of the cells with the patient's pretreatment gammaG-globulins resulted in a release of 40% of the radioactive heme from the cells. This represented the loss of radioactive hemoglobin and was an index of erythroblast cytotoxicity. A progressive disappearance of the cytotoxic factor in the gammaG-globulins occurred in the 3 wk period preceding the onset of reticulocytes in the patient's blood. Posttreatment and normal gammaG-globulins did not produce this effect and increased injury of red cells and lymphocytes was not produced by the patient's pretreatment gammaG-globulins. These studies demonstrate a method for measuring erythroblast cytoxicity and show that red cell aplasia is associated with gammaG-globulins that specifically damage erythroblasts. Whether interference with new erythroblast development also occurs and contributes to the inhibition of heme synthesis has not yet been ascertained.

Anemia, Aplastic↗