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On the primary structure of human plasminogen and plasmin. Purification and characterization of cyanogen-bromide fragments.

Most of the cyanogen bromide fragments obtained from human plasminogen and plasmin have been purified using combinations of gel filtration and ion-exchange chromatography. The purified fragments have been characterized by molecular weight determination (dodecyl sulphate electrophoresis), amino acid analysis, carbohydrate analysis and direct NH2-terminal amino acid sequence determination. Since some of the purified fragments were compounds with uncompletely cleaved methionyl bonds it was possible to clarify the organization of most of the cyanogen bromide fragments in the plasminogen molecule. The fragment containing the arginyl-valyl bond cleaved during the second step of the activation process is further identified. It is also shown that the microheterogeneity that normally exists in human plasminogen probably has its origin in several sites. One such site is situated in the light (B) chain of plasmin, while another is situated in the carboxyterminal part of the heavy (A) chain. Neither of these sites seems to contain sialic acid.

Amino Acid Sequence↗

Structural studies on the coat protein of alfalfa mosaic virus. Isolation and characterization of the tryptic peptides and the alignment of the cyanogen-bromide fragments.

The reduced and carboxymethylated coat protein of alfalfa mosaic virus (AMV 425) was fragmented by means of cyanogen-bromide cleavage. The tryptic peptides from the protein and its four cyanogen-bromide fragments were isolated on a preparative scale by combinations of column and paper separation techniques. The tryptic digest of the carboxymethylated protein contained 24 peptides and two free amino acids. All peptides have been characterized by amino acid analyses and end-group determinations. Together the tryptic peptides account for a total chain length of 228 amino acids. The data are in good agreement with previous reports from this laboratory.

Amino Acid Sequence↗

Antigenic structure of the cyanogen bromide peptide F-CB3 from fibrinogen alpha-chain.

The antigenic properties of the cyanogen bromide peptide F-CB3 from bovine fibrinogen alpha-chain were studied in radioimmune assays with rabbit antibodies to fibrinogen or to peptide F-CB3. Both fibrinogen and peptide F-CB3 were indistinguishable in inhibition and dissociation tests. Modification of the single disulfide bridge in peptide F-CB3 either by reduction or by cleavage with cyanide was not accompanied by loss of serologic activity. Inhibition studies with three individual fragments obtained after cyanide cleavage (molecular weight range 7000 to 23000) indicated the presence of at least three distinct antigenic determinants in peptide F-CB3. After trypsin digestion of peptide F-CB3 still 75% of its maximal inhibiting capacity was retained. Lack of change in antigenic activity of peptide F-CB3 after release from the fibrinogen molecule by cyanogen bromide and upon further fragmentation is presumably due to the presence of several sequential antigenic determinants but the presence of conformational determinants could not be entirely excluded. Since no cross-reaction was observed between bovine and human peptides F-B3 one may expect considerable variation in their amino acid sequence.

Animals↗

Isolation of a crosslinked cyanogen-bromide peptide from insoluble rabbit collagen. Tissue differences in hydroxylation and glycosylation of the crosslink.

A radioactive peptide has been isolated from cyanogen bromide digests of sodium boro[3H]-hydride-reduced collagen from rabbit bone, tendon and skin. It was identified as a crosslinked peptide linking the short C-terminal cyanogen bromide peptide alpha1-CB6B (17 amino acid residues) to alpha1-CB5 (37 residues) from the helical part of the chain of an adjacent molecule. Both peptides could be separated after cleaving the crosslink with periodate. Thus the crosslinked peptide alpha1-CB5 X alpha1-CB6B originates from an intermolecular crosslink between quarter-staggered molecules within collagen fibrils previously assigned as 'head-to-tail' link. The chemical nature of the reduced crosslinking component was identified and was shown to differ between peptides derived from different tissues: alpha1-CB6B X alpha1 CB5 from bone contains hydroxylysinohydroxynorleucine [o5Lys(o5omegaNle)] whereas the skin peptide contains hydroxylysinonorleucine [o5Lys(omegaNle)]. The peptide derived from tendon contains both components. The relation of o5Lys(omegaNle) to o5Lys(o5omegaNle) in the peptides corresponds to that of the original tissue. On the other hand, histidino-hydroxymerodesmosine which is a major reduced cross-linking component in skin and tendon, is completely absent in the isolated peptides. The crosslinking component in the skin peptide is completely glycosylated, mainly by glucosylgalactosyl residues and to a smaller extent by galactosyl residues. o5Lys(o5omegaNle) from the bone peptide is only partly glycosylated, containing equal amounts of the disaccharide and monosaccharide. Only slight glycosylation was found in the tendon peptide.

Amino Acid Sequence↗

Amino acid sequence studies of horseradish peroxidase. Amino and carboxyl termini, cyanogen bromide and tryptic fragments, the complete sequence, and some structural characteristics of horseradish peroxidase C.

Horseradish peroxidase C dominates quantitatively among the isoperoxidases of horseradish root and has an isoelectric point close to 9. It consists of a hemin prosthetic group, 2 Ca2+ and 308 amino acid residues, including 4 disulfide bridges, in a single polypeptide chain that carries 8 neutral carbohydrate side-chains. The molecular weight of the polypeptide chain is 33890. Assuming an average carbohydrate composition of (GlcNAc)2, Man3, Fuc, Xyl for each carbohydrate chain, the molecular weight of native horseradish peroxidase C is close to 44 000. Cyanogen bromide fragments of reduced and carboxymethylated apo-peroxidase were purified by a combination of gel filtration and isoelectric focusing in urea, and cystine-containing tryptic fragments of apo-peroxidase were purified by gel filtration followed by disulfide cleavage and rechromatography at the initial conditions. The present paper discusses (a) isoelectric points and charge distribution within the native protein, the apoprotein and the cyanogen bromide fragments, (b) a buried pyrrolidonecarboxylyl amino terminus, (c) heterogeneity at the carboxyl terminus, and (d) a possible domain structure, likely from partial tryptic digestion.

Amino Acid Sequence↗

Efficacy of hyoscine-N-butyl bromide (Buscopan) suppositories as a cervical spasmolytic agent in labour.

OBJECTIVE: To evaluate the efficacy and safety of hyoscine-N-butyl bromide (Buscopan) suppositories in the active phase of labour, i.e. once the labour is established. METHODS: A non-randomised controlled prospective study was carried out on 200 women in labour. In the active phase of labour, at 3 cm or more cervical dilatation, 100 women were administered Buscopan via suppository and 100 women (control) were not given any drug. RESULTS: The duration of first stage of labour was 123.86 +/- 68.89 (mean(+)-standard deviation) minutes in the study group and 368.05 +/- 133.0 min in the control group. These differences were statistically significant. There were no differences in the duration of the second and third stages of labour. There was no increased incidence of operative deliveries in the study group. No adverse effects were noted on the mother or fetus. CONCLUSION: Hyoscine-N-butyl bromide (HBB, Buscopan) suppositories were highly effective in shortening the duration of the first stage of labour.

Administration, Intravaginal↗

Preparation of solid-phase immunosorbents by coupling human serum proteins to cyanogen bromide-activated agarose.

The method of preparing solid-phase immunosorbents by covalently attaching proteins from whole human serum to cyanogen bromide-activated agarose has been investigated to determine optimum concentrations of cyanogen bromide and protein, and the optimum pH for the maximum attachment of proteins from serum. Two systems in which the above immunosorbents have proved useful are described: the removal of antibodies to normal serum proteins from anti-hepatitis B serum and the removal of light chain antibodies from anti-human immunoglobulin M serum.

Absorption↗

Extraction of streptococcal type 12 M protein by cyanogen bromide.

Conditions for the release of streptococcal type 12 M protein from whole cells by cyanogen bromide are described; they demonstrated that methionine is not essential to the structural arrangements which account for some of its immunological and biological properties. The released M protein was separated from other proteins by column chromatography with hydroxylapatite. The type-specific molecules which reacted with precipitating antibodies were found only in the 0.3 M eluate, formed zones with mobilities less than 12% of that of the dye front on electrophoresis in the standard acrylamide disc gel system, formed at least four bands in sodium dodecyl sulfate-acrylamide disc gels with molecular weights ranging from 12,000 to 23,000, and stimulated the formation of opsonic antibodies in rabbits. Cyanogen bromide provides a highly specific method for the release of M proteins which should prove particularly useful in analyses of structural-functional relationships among different M proteins.

Amino Acids↗

Separation and characterization of a 14,000-dalton cyanogen bromide-generated peptide from a 185,000-dalton streptococcal antigen.

The cell surface streptococcal antigen (SA) (185,000 molecular weight [185K SA]) was isolated from Streptococcus mutans and digested with cyanogen bromide. Three major products with molecular weights of 100,000, 50,000, and 14,000 appeared within 1 h of digestion. Time course studies of digestion by polyacrylamide gel electrophoresis showed maximal intensity of the 14K band after 8 h. However, other bands appeared as well, notably 70K and 20K bands. Several bands were eluted from the gels, and their antigenicity was studied. They reacted with antisera to the native 185K SA I/II, as well as with those to the SA I and SA II antigens, though antibody binding by radioimmunoassay was significantly lower than that with the native SA. The 14K SA was identified on Western blots (immunoblots) with anti-SA I/II, I, and II antisera. The digested SAs were then tested for their immunogenicity by injecting CBA mice with the separated SA mixed in complete Freund adjuvant. Whereas the unseparated cyanogen bromide-treated SA and separated 70K and 20K SAs were immunogenic, the 14K SA failed to elicit serum antibodies. Further investigation of the 14K SA revealed that although it is apparently not immunogenic, it can induce a primary antibody response in mice when followed by the native 185K SA and a secondary response when mice are immunized first with the 185K SA.

Animals↗

Purification, cyanogen bromide cleavage, and amino terminus sequencing of class 1 and class 3 outer membrane proteins of meningococci.

Meningococcal class 1 and 3 outer membrane proteins (OMPs) were subjected to cyanogen bromide treatment. The class 3 OMP was found to be resistant to cyanogen bromide, while the class 1 OMP was cut into two main fragments of 25 and 17 kilodaltons. The N-terminal sequences were determined for class 1 and class 3 proteins, which exhibit similarities to one another and to OMP I of gonococci. The C-terminal class 1 OMP fragment bound the bactericidal monoclonal antibodies tested.

Amino Acid Sequence↗

Lysine 2,3-aminomutase from Clostridium subterminale SB4: mass spectral characterization of cyanogen bromide-treated peptides and cloning, sequencing, and expression of the gene kamA in Escherichia coli.

Lysine 2,3-aminomutase (KAM, EC 5.4.3.2.) catalyzes the interconversion of L-lysine and L-beta-lysine, the first step in lysine degradation in Clostridium subterminale SB4. KAM requires S-adenosylmethionine (SAM), which mediates hydrogen transfer in a mechanism analogous to adenosylcobalamin-dependent reactions. KAM also contains an iron-sulfur cluster and requires pyridoxal 5'-phosphate (PLP) for activity. In the present work, we report the cloning and nucleotide sequencing of the gene kamA for C. subterminale SB4 KAM and conditions for its expression in Escherichia coli. The cyanogen bromide peptides were isolated and characterized by mass spectral analysis and, for selected peptides, amino acid and N-terminal amino acid sequence analysis. PCR was performed with degenerate oligonucleotide primers and C. subterminale SB4 chromosomal DNA to produce a portion of kamA containing 1,029 base pairs of the gene. The complete gene was obtained from a genomic library of C. subterminale SB4 chromosomal DNA by use of DNA probe analysis based on the 1,029-base pair fragment. The full-length gene consisted of 1,251 base pairs specifying a protein of 47,030 Da, in reasonable agreement with 47, 173 Da obtained by electrospray mass spectrometry of the purified enzyme. N- and C-terminal amino acid analysis of KAM and its cyanogen bromide peptides firmly correlated its amino acid sequence with the nucleotide sequence of kamA. A survey of bacterial genome databases identified seven homologs with 31 to 72% sequence identity to KAM, none of which were known enzymes. An E. coli expression system consisting of pET 23a(+) plus kamA yielded unsatisfactory expression and bacterial growth. Codon usage in kamA includes the use of AGA for all 29 arginine residues. AGA is rarely used in E. coli, and arginine clusters at positions 4 and 5, 25 and 27, and 134, 135, and 136 apparently compound the barrier to expression. Coexpression of E. coli argU dramatically enhanced both cell growth and expression of KAM. Purified recombinant KAM is equivalent to that purified from C. subterminale SB4.

Amino Acid Sequence↗

Separation of cyanogen bromide-cleaved peptides of the vesicular stomatitis virus glycoprotein and analysis of their carbohydrate content.

The purified glycoprotein of vesicular stomatitis virus was cleaved at methionine residues with cyanogen bromide, and the resultant peptides were analyzed by two-dimensional electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. Five peptide bands were resolved in cylindrical gels run under nonreducing conditions. After reduction and electrophoresis in the second dimension, 11 peptides were resolved, indicating that several were originally linked by disulfide bonds. Double-label experiments indicated that at least 8 of the 11 peptides were unique. The major oligosaccharide chains were attached to two different cyanogen bromide peptides. In addition, six other peptides contained small amounts of sialic acid, fucose, and mannose, indicating that the glycoprotein contains more carbohydrate chains than the two major ones which have been reported previously.

Amino Acids↗

Radioactive bromide partition test in differential diagnosis of tuberculous meningitis.

In 19 cases of lymphocytic meningitis, the radioactive bromide partition test showed that four were tuberculous and 15 viral in origin. In all the tuberculous cases the serum/cerebrospinal fluid bromide ratio was below a critical value of 1.6, and in all the cases of viral meningitis the ratio was above this value. The test may be particularly helpful when diagnosis is difficult. The test may prove to be a valuable and justified additional procedure in the early diagnosis of tuberculous meningitis.

Adolescent↗

Positive bromide partition test in the absence of tuberculous meningitis.

Five cases of lymphocytic meningitis are described where a Bromide Partition Test was performed and proved positive at levels usually considered consistent with tuberculous meningitis. Three of these cases were ultimately shown to have herpes simplex viral encephalitis, one had Listeria monocytogenes in the CSF and the fifth patient recovered without treatment and was thought to have had a viral encephalitis. The Bromide Partition Test may not be as good a discriminant as has previously been suggested in differentiating between tuberculous and viral meningitis, especially when performed in a population at low risk of getting tuberculous meningitis.

Adolescent↗

Mapping of proteolytic and cyanogen bromide peptides from subunits of intestinal maltase-glucoamylase: evidence for significant homology.

Rat intestinal maltase-glucoamylase was purified in the presence of detergent and proteolytic inhibitors, and the 130000 and 145000 subunits were separated and isolated by preparative sodium dodecyl sulfate - polyacrylamide gel electrophoresis and electrophoretic elution. Amino acid analyses were very similar, with a small excess of apolar amino acid residues in the 145000 subunit. Peptide mapping with Staphylococcus aureus V8 protease revealed eight similar peptide products for each, with apparent elongation of the five larger peptides in the 145000 subunit by a relative mass (Mr) of 2000-5000. alpha-Chymotrypsin maps showed at least eight identical cleavage products plus one large, shared product which was larger by a Mr of 5000 in the 145000 subunit. Cyanogen bromide cleavage of the 145000 subunit produced a single peptide of Mr 75000. A peptide of Mr 66000, also indicative of a central cleavage, was generated from the 130000 subunit, but a second cleavage into 43000 and 23000 segments was also evident. Several sets of antibodies formed against both antigens consistently gave reactions of identity without spurring on immunodiffusion. These results indicate extreme homology between the central segment of the 145000 subunit and the 130000 subunit. The cyanogen bromide cleavage results suggest, however, that the two central sequences are not absolutely identical and therefore that one subunit may not be a posttranslational derivative of the other.

Amino Acids↗

Myopathic alterations in extraocular muscle of rats subchronically fed pyridostigmine bromide.

To determine if alterations in extraocular muscle morphology occur after subchronic oral administration of pyridostigmine bromide, rats were continuously fed 90 mg/kg in meal and examined at 1, 2, 4, 7, and 15 days. Within the first day, blood acetylcholinesterase activity was reduced by 87% and remained inhibited by 74-91% during the study. Light microscopy demonstrated that by day 1 approximately 3% of the extraocular myofibers were shrunken and invaded by inflammatory cells. The most severe degenerative changes consisting of vacuoles and inflammatory cell infiltration occurred at day 1 with progressively less severe changes at days 2 and 4. At days 7 and 15, 1.3-4.5% of the myofibers still exhibited damage. Ultrastructurally, all presynaptic areas were normal but the postsynaptic areas of affected myofibers at days 1, 2, and 4 showed myofilament and Z-band dissolution, mitochondrial inclusions, subneural fold and T-tubule/sarcoplasmic reticulum vacuolization and subneural fold depth reduction. By days 7 and 15, these changes were diminished in some cases and in others alterations appeared similar to day 1. We conclude that subchronic feeding of pyridostigmine bromide induces myopathic rather than neurogenic changes in rat extraocular muscle and that the myopathy is different in these muscles than in the diaphragm from the the same rats.

Animals↗

Paradoxical halide levels in bromide intoxication.

In two patients with acute bromide toxicity, serum bromide levels rose during the period of observation, but this increase was not associated with clinical deterioration. In both, serum "chloride" levels were also high, but these values actually indicated elevated extracellular halide concentrations.

Adult↗

Metal affinity engineering of proinsulin carrying genetically attached (His)10-X-Met affinity tail and removal of the tag by cyanogen bromide.

An E. coli expression clone coding for human proinsulin, which was fused to NH2-terminal beta-galactosidase, was engineered for the separation from host proteins by introducing peptide devices, and for the sequential removal of the fused polypeptide by cyanogen bromide in front of the NH2 terminal residue (methionine) of the human proinsulin gene. Short synthetic genes encoding oligopeptide residues including (Glu)n, (His)n, (Trp)n, and (Ser)n (n = 10 or 11), which have certain characteristic physical properties such as metal-affinity, polarity, hydrophobicity, and hydrophilicity, respectively, were inserted at the junction region of the gene fusion. Interestingly, it was found that among the oligopeptides, the oligohistidine residue as an affinity-tag has greatly facilitated the procedures for FPI purification, particularly in the manner of selective metal-affinity precipitation. The chelating peptide covering the NH2-terminal beta-galactosidase portion could then be removed simply after purification to generate a protein with the natural amino acid sequence of proinsulin by cyanogen bromide.

Affinity Labels↗