scholarly journals Pig kidney legumain: an asparaginyl endopeptidase with restricted specificity

1999 ◽  
Vol 339 (3) ◽  
pp. 743-749 ◽  
Author(s):  
Pam M. DANDO ◽  
Mara FORTUNATO ◽  
Lorraine SMITH ◽  
C. Graham KNIGHT ◽  
John E. MCKENDRICK ◽  
...  
Keyword(s):  
Mhc Class Ii ◽  
Tetanus Toxin ◽  
Tertiary Butyl ◽  
Asparaginyl Endopeptidase ◽  
Pig Kidney ◽  
Bait Region ◽  
Substrate Analogues ◽  
Α2 Macroglobulin ◽  
Hydrolysis Of ◽  
Asparagine Residue

Legumain was recently discovered as a lysosomal endopeptidase in mammals [Chen, Dando, Rawlings, Brown, Young, Stevens, Hewitt, Watts and Barrett (1997) J. Biol. Chem. 272, 8090-8098], having been known previously only from plants and invertebrates. It has been shown to play a key role in processing of the C fragment of tetanus toxin for presentation by the MHC class-II system [Manoury, Hewitt, Morrice, Dando, Barrett and Watts (1998) Nature (London) 396, 695-699]. We examine here the specificity of the enzyme from pig kidney by use of protein, oligopeptide and synthetic arylamide substrates, all determinations being made at pH 5.8. In proteins, only about one in ten of the asparaginyl bonds were hydrolysed, and these were mostly predicted to be located at turns on the protein surface. Bonds that were not cleaved in tetanus toxin were cleaved when presented in oligopeptides, sometimes faster than an equivalent oligopeptide based on a bond that was cleaved in the protein. Legumain cleaved the bait region of rat α1-macroglobulin and was ‘trapped’ by the macroglobulin, as most other endopeptidases are, but did not interact with human α2-macroglobulin, which contains no asparagine residue in its bait region. Glycosylation of asparagine totally prevented hydrolysis by legumain. Specificity for arylamide substrates was evaluated with reference to benzyloxycarbonyl-Ala-Ala-Asn-aminomethylcoumarin, and the preference for the P3-position amino acid was Ala > Tyr(tertiary butyl) > Val > Pro > Phe = Tyr > Leu = Gly. There was no hydrolysis of substrate analogues containing mono- or di-N-methylasparagines, L-2-amino-3-ureidopropionic acid or citrulline in the P1 position. We conclude that mammalian legumain appears to be totally restricted to the hydrolysis of asparaginyl bonds in substrates of all kinds. There seem to be no strong preferences for particular amino acids in other subsites, and yet there are still unidentified factors that prevent hydrolysis of many asparaginyl bonds in proteins.

scholarly journals Characterization of Legumain

2002 ◽  
Vol 383 (11) ◽  
pp. 1813-1816 ◽  
Author(s):  
G. Schwarz ◽  
J. Brandenburg ◽  
M. Reich ◽  
T. Burster ◽  
C. Driessen ◽  
...  
Keyword(s):  
Mhc Class Ii ◽  
Basic Protein ◽  
Critical Role ◽  
Immunodominant Epitope ◽  
Alternative Substrate ◽  
Asparaginyl Endopeptidase ◽  
Pig Kidney ◽  
Different Types ◽  
Antigen Presenting

Abstract The mammalian legumain, also called asparaginyl endopeptidase (AEP), is critically involved in the processing of bacterial antigens for MHC class II presentation. In order to investigate the substrate specificity of AEP in the P1 position, we created a peptide library and digested it with purified pig kidney AEP. Digestion was less efficient only when proline was in the P1 position. Maximum AEP activity was found in lysosomal fractions of different types of antigen presenting cells (APC). When the multiple sclerosisassociated autoantigen myelin basic protein (MBP) was digested with AEP, the immunodominant epitope 8399 was destroyed. Myoglobin as an alternative substrate was AEP resistant. These results suggest an important, but not necessarily critical role for AEP in lysosomal antigen degradation.

scholarly journals Development of selective protease inhibitors via engineering of the bait region of human α2-macroglobulin

2021 ◽  
pp. 100879
Author(s):  
Seandean Lykke Harwood ◽  
Nadia Sukusu Nielsen ◽  
Khang Diep ◽  
Kathrine Tejlgård Jensen ◽  
Peter Kresten Nielsen ◽  
...  
Keyword(s):  
Protease Inhibitors ◽  
Bait Region ◽  
Α2 Macroglobulin

scholarly journals The metabolism of neuropeptides. Neurokinin A (substance K) is a substrate for endopeptidase-24.11 but not for peptidyl dipeptidase A (angiotensin-converting enzyme)

1985 ◽  
Vol 231 (2) ◽  
pp. 357-361 ◽  
Author(s):  
N M Hooper ◽  
A J Kenny ◽  
A J Turner
Keyword(s):  
Substance P ◽  
Selective Inhibitor ◽  
Synaptic Membranes ◽  
Neurokinin A ◽  
Pig Kidney ◽  
Endopeptidase 24.11 ◽  
The Family ◽  
General Capacity ◽  
Substance K ◽  
Hydrolysis Of

Both endopeptidase-24.11 and peptidyl dipeptidase A have previously been shown to hydrolyse the neuropeptide substance P. The structurally related peptide neurokinin A is also shown to be hydrolysed by pig kidney endopeptidase-24.11. The identified products indicated hydrolysis at two sites, Ser5-Phe6 and Gly8-Leu9, consistent with the known specificity of the enzyme. The pattern of hydrolysis of neurokinin A by synaptic membranes prepared from pig striatum was similar to that observed with purified endopeptidase-24.11, and hydrolysis was substantially abolished by the selective inhibitor phosphoramidon. Peptidyl dipeptidase A purified from pig kidney was shown to hydrolyse substance P but not neurokinin A. It is concluded that endopeptidase-24.11 has the general capacity to hydrolyse and inactivate the family of tachykinin peptides, including substance P and neurokinin A.

The β-glucosidases of porcine kidney

1977 ◽  
Vol 55 (2) ◽  
pp. 140-145 ◽  
Author(s):  
Julian N. Kanfer ◽  
Richard A. Mumford ◽  
Srinivasa S. Raghavan
Keyword(s):  
Sodium Taurocholate ◽  
Hydrolytic Activity ◽  
Acidic Ph ◽  
Porcine Kidney ◽  
Ph Optimum ◽  
Pig Kidney ◽  
Competitive Inhibitors ◽  
Triton X ◽  
Hydrolysis Of ◽  
Estradiol 17Β

Some of the properties of a partially purified particle bound and soluble β-glucosidase (EC 3.2.1.21) from pig kidney were compared. The soluble β-glucosidase (1) hydrolyzed 4-methylumbelliferyl-β-D-glucoside (4-MU-β-D-glucoside) 17α-estradiol 3β-glucoside, 17α-estradiol 17β-glucoside, and salicin, but not glucosylceramide, (2) possessed a broad pH optimum (5.5–7.0), (3) had an isoelectric point of 4.9, and (4) was inhibited by Triton X-100. Several compounds were found to be competitive inhibitors of its hydrolytic activity, gluconolactam and estrone β-glucoside being the most effective. In contrast, a particulate β-glucosidase purified from the same tissue (1) had an acidic pH optimum (5.0), (2) was stimulated by sodium taurocholate and 'Gaucher's factor' for the hydrolysis of both 4-MU-β-glucoside and glucosylceramide, and (3) was capable of catalyzing a transglucosylation reaction employing 4-MU-β-D-glucoside or glucosylceramide as the glucosyl donor, and [l4C]ceramide as acceptor.

Elastase inhibitors in sputum from bronchitic patients with and without α1-proteinase inhibitor deficiency: partial characterization of a hitherto unquantified inhibitor of neutrophil elastase

1987 ◽  
Vol 73 (1) ◽  
pp. 19-28 ◽  
Author(s):  
H. M. Morrison ◽  
J. A. Kramps ◽  
S. C. Afford ◽  
D. Burnett ◽  
J. H. Dijkman ◽  
...  
Keyword(s):  
Neutrophil Elastase ◽  
Proteinase Inhibitor ◽  
Gel Filtration ◽  
Prolonged Incubation ◽  
Α2 Macroglobulin ◽  
Group A ◽  
Hydrolysis Of ◽  
Molecular Weight Fractions ◽  
Deficient Group

1. Anti-elastase function in sputum sol-phase from patients with α1-proteinase inhibitor (α1PI) deficiency was compared with sol-phase from patients with cigarette smoke-induced bronchitis and emphysema. 2. Both α1PI (2P < 0.01) and anti-leucoprotease (ALP) (2P < 0.01) concentrations were lower in sol-phase from the α1PI-deficient group, although α2-macroglobulin (α2M) levels were similar. 3. There was no difference in α1PI function between the two groups, but the inhibitor was only ≃ 30% active. 4. The absolute neutrophil elastase (NE) inhibitory capacity was similar in both groups (median 185 μg of NE inhibited/ml of sputum, range 80–480, for the α1PI-deficient group; median 175, range 80–300, for the bronchitic group). A substantial proportion of NE inhibition in secretions could not be accounted for by the amount of α1PI, ALP and α2M present (median 74.8%, range 43.2–97.4, for α1PI-deficient sol-phase; median 50.0%, range 0–80.8, for bronchitic sol-phase). 5. Gel filtration of sol-phase demonstrated the presence of NE inhibition in the low molecular weight fractions which was markedly sensitive to changes in substrate concentration and ionic strength, in contrast to purified α1PI and ALP. 6. Sputum sol-phase from both groups failed to prevent hydrolysis of elastin–fluorescein or succinyltrialanyl-p-nitroanilide by NE completely during prolonged incubation in the presence of an excess of functional inhibitors. This was more apparent in secretions from subjects with α1PI deficiency and may explain why such patients have a more rapidly progressive form of emphysema.

scholarly journals Further evidence for an allosteric model for ribonuclease

1976 ◽  
Vol 153 (2) ◽  
pp. 329-337 ◽  
Author(s):  
E J Walker ◽  
G B Ralston ◽  
I G Darvey
Keyword(s):  
Conformational Change ◽  
Equilibrium Dialysis ◽  
Kinetic Studies ◽  
Experimental Systems ◽  
Substrate Analogues ◽  
Multiple Binding ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Cyclic Cmp ◽  
Allosteric Model

Evidence is presented from three experimental systems to support the allosteric model of Walker et al. (1975) (Biochem. J. 147, 425-433) which explains the substrate-concentration-dependent transition observed in the RNAase (ribonuclease)-catalysed hydrolysis of 2‘:3’-cyclic CMP (cytidine 2‘:3’-cyclic monophosphate). 1. Kinetic studies of the initial rate of hydrolysis of 2‘:3’-cyclic CMP show that the midpoint of the transition shifts to lower concentrations of 2‘:3’-cyclic CMP in the presence of the substrate analogues 3′-CMP, 5′-CMP, 3′-AMP, 3′-UMP and Pi; 2′-CMP and 2′-UMP do not cause such a shift. 2. Trypsin-digestion studies show that a conformational change in RNAase to a form less susceptible to tryptic inactivation is induced in the presence of the substrate analogues 3′-CMP, 5′-CMP, 3′-AMP, and 3′-UMP. 2′-CMP, 2′-AMP and 2′-UMP do not induce this conformational change. 3. Equilibrium-dialysis experiments demonstrate the multiple binding of molecules of 3′-CMP, 3′-AMP and 5′-AMP to a molecule of RNAase. 2′-CMP binds the ratio 1:1 over the analogue concentration range studied.

scholarly journals Structural and functional insights into Escherichia coli α2-macroglobulin endopeptidase snap-trap inhibition

2015 ◽  
Vol 112 (27) ◽  
pp. 8290-8295 ◽  
Author(s):  
Irene Garcia-Ferrer ◽  
Pedro Arêde ◽  
Josué Gómez-Blanco ◽  
Daniel Luque ◽  
Stephane Duquerroy ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Envelope ◽  
Large Cell ◽  
Structural Rearrangement ◽  
Gram Negative Bacteria ◽  
Human Gut ◽  
Bait Region ◽  
Α2 Macroglobulin ◽  
Thioester Bond ◽  
Peptidase Inhibitor

The survival of commensal bacteria requires them to evade host peptidases. Gram-negative bacteria from the human gut microbiome encode a relative of the human endopeptidase inhibitor, α2-macroglobulin (α2M). Escherichia coli α2M (ECAM) is a ∼180-kDa multidomain membrane-anchored pan-peptidase inhibitor, which is cleaved by host endopeptidases in an accessible bait region. Structural studies by electron microscopy and crystallography reveal that this cleavage causes major structural rearrangement of more than half the 13-domain structure from a native to a compact induced form. It also exposes a reactive thioester bond, which covalently traps the peptidase. Subsequently, peptidase-laden ECAM is shed from the membrane and may dimerize. Trapped peptidases are still active except against very large substrates, so inhibition potentially prevents damage of large cell envelope components, but not host digestion. Mechanistically, these results document a novel monomeric “snap trap.”

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