Localization of the two protease binding sites in human alpha 2-macroglobulin.

François, Patrice; Favaudon, Vincent; Tourbez-Perrin, M.; Bieth, Joseph G.

doi:10.1016/s0021-9258(19)70001-5

Cited by 59 publications

(23 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…be expected, reasonably close to the observed ratio of 1:2.6. The observed ratio for human a2-macroglobulin is consistent with the reported maximum stoichiometry of proteinase binding to tetrameric a2-macroglobulin (Ganrot, 1966;Barrett et al, 1979;Swenson & Howard, 1979a;Sottrup-Jensen et al, 1980;Pochon et al, 1981;Howell et al, 1983;Bj6rk, 1984;Bjork et al, 1984;Straight & McKee, 1984) and the report that all thiol ester groups are activated during reaction with proteinase (Bjork et al, 1984;Feinman et al, 1985). The presence of a protein functionally and structurally homologous to a2-macroglobulin in an arthropod suggests that the protein appeared in evolution before the divergence of the arthropod and vertebrate lineages 0.55 x 109 years ago.…”

Section: -supporting

confidence: 88%

Limulus α2-macroglobulin. First evidence in an invertebrate for a protein containing an internal thiol ester bond

Armstrong

Quigley

1987

Biochemical Journal

View full text Add to dashboard Cite

Intra-chain thiol ester bonds are present in a limited number of proteins. The thiol ester class of proteins includes vertebrate alpha 2-macroglobulin and the complement proteins C3 and C4. We report here the first instance of a thiol ester protein from an invertebrate, the alpha 2-macroglobulin proteinase-inhibitor homologue present in the plasma of the American horseshoe crab Limulus polyphemus. Our evidence is of three kinds: (1) the proteinase-binding activity of Limulus alpha 2-macroglobulin is inactivated by the low-molecular-mass primary amine methylamine; (2) the native protein is subject to autolytic fragmentation during mild thermal denaturation, yielding fragments of approx. 125 kDa and 55 kDa, whereas the methylamine-treated protein is stable under these conditions of thermal treatment; (3) new thiol groups are generated rapidly during reaction of the protein with trypsin. The demonstration of the thiol ester bond in a protein from an ancient invertebrate provides evolutionary evidence for the importance of this bond in the function of plasma forms of the alpha 2-macroglobulin-like proteinase inhibitors.

show abstract

Section: -supporting

confidence: 88%

Limulus α2-macroglobulin. First evidence in an invertebrate for a protein containing an internal thiol ester bond

Armstrong

Quigley

1987

Biochemical Journal

View full text Add to dashboard Cite

show abstract

“…The amount of protease bound to a2M depends upon its size. Proteases such as trypsin and chymotrypsin are bound in a 2:1 (mol/mol, protease to a2M) stoichiometry (Bieth et al, 1970;Pochon et al, 1981). With larger proteases, such as plasmin, the results are not as clearly documented.…”

mentioning

confidence: 98%

“…With larger proteases, such as plasmin, the results are not as clearly documented. Ratios of plasmin to a2M (mol/mol) ranging from 1:1 (Ganrot, 1966;Pochon et al, 1981;Howell et al, 1983) to 2:1 (Straight & McKee, 1982) have been reported.Many of these proteases, when complexed to a2M, retain, to various degrees, their ability to hydrolyze small substrates but show greatly decreased activity toward larger substrates [see Barrett & Starkey (1973) for a review]. The binding of these endoproteases to a2M occurs in several stages.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Interaction of human plasmin with human .alpha.2-macroglobulin

Cummings¹

1984

Biochemistry

View full text Add to dashboard Cite

The steady-state kinetic parameters of plasmin and the alpha 2-macroglobulin (alpha 2M)-plasmin complex toward the chromogenic substrate Val-Leu-Lys-p-nitroanilide (S-2251), in the presence and absence of plasmin competitive inhibitors, have been determined. At pH 7.4 and 22 degrees C, the Km values for plasmin and alpha 2M-plasmin for S-2251 were 0.13 +/- 0.02 mM and 0.3 +/- 0.03 mM. The kcat of this reaction, when catalyzed by alpha 2M-plasmin, was 6.0 +/- 0.5 s-1, a value significantly decreased from the kcat of 11.0 +/- 1.0 s-1, determined when free plasmin was the enzyme. KI values for benzamidine of 0.50 +/- 0.05 mM and 0.23 +/- 0.02 mM were obtained for S-2251 hydrolysis, as catalyzed by alpha 2M-plasmin and plasmin, respectively. When leupeptin was the competitive inhibitor, KI values of 5.0 +/- 0.65 microM and 1.0 +/- 0.1 microM were obtained when alpha 2M-plasmin and plasmin, respectively, were the enzymes employed for catalysis of S-2251 hydrolysis. The comparative rates of reaction of the peptide inhibitor Trasylol (Kunitz basic pancreatic inhibitor) with plasmin and alpha 2M-plasmin were also determined. A concentration of Trasylol of at least 3 orders of magnitude greater for alpha 2M-plasmin than for free plasmin was required to observe inhibition rates on comparable time scales.(ABSTRACT TRUNCATED AT 250 WORDS)

show abstract

“…(iii) For urea, the same schedule as for ionic strength was applied, with I M urea increments, to reach a final concentration of 4 M. (iv) For proteinase K (Merck), freshly harvested viruses were diluted 10 times, digested by 50 j.ig of proteinase K per ml (1:20 [vol/vol]) for 1 h at 37°C, and set to the final dilution. For chymotrypsin, bovine pancreatic chymotrypsin specially purified by F. Pochon for other purposes (37) was applied to the virus suspension at a concentration of 50 pLg/ml for 1 h at 37°C in 20 mM N-2-hydroxyethylpiperazine-N'-2ethanesulfonic acid (HEPES)-50 mM NaCl, pH 7.2. (v) For detergents, Triton X-100 (0.04 to 0.1% [vol/vol]) was added to the viral sample for 2 min before the addition of urea (usually 2 M).…”

Section: Methodsmentioning

confidence: 99%

Electron microscopy of the nucleocapsid from disrupted Moloney murine leukemia virus and of associated type VI collagen-like filaments

Pager

Coulaud

Delain

1994

J Virol

View full text Add to dashboard Cite

To analyze the constituents of retroviruses, the Moloney murine leukemia virus was disrupted and observed by dark-field electron microscopy. Virus disruption was achieved by several methods: osmotic shock, freezing-thawing cycles, and exposure to urea up to 4 M, to NaCl up to 1 M, and to Triton X-100. Several components associated with broken Moloney murine leukemia virus were repeatedly found in preparations. These components have been described as rings, thick filaments, chain-like filaments, threads covered with proteins, threads with buckles, and naked threads. A quantitative analysis of the occurrence of these components has been carried out. Among them, the thick filaments composed of a compact helical arrangement of small beads 5 nm in diameter were considered to represent the nucleocapsid. The protease-sensitive buckles found on some threads could be a compact form of the viral RNA associated to the nucleocapsid protein NCp10. The RNase-sensitive naked threads are interpreted as the deproteinized viral RNA itself. The ubiquitous chain-like filaments possess a periodic structure identical to that of polymerized type VI collagen. It is proposed that this adhesive protein is associated with the viral envelope taken from the cell membrane during the budding process of retroviruses.

show abstract

Localization of the two protease binding sites in human alpha 2-macroglobulin.

Cited by 59 publications

References 24 publications

Limulus α2-macroglobulin. First evidence in an invertebrate for a protein containing an internal thiol ester bond

Limulus α2-macroglobulin. First evidence in an invertebrate for a protein containing an internal thiol ester bond

Interaction of human plasmin with human .alpha.2-macroglobulin

Electron microscopy of the nucleocapsid from disrupted Moloney murine leukemia virus and of associated type VI collagen-like filaments

Contact Info

Product

Resources

About