Isolation and characterization of the four major cysteine-proteinase components of the latex of carica papaya L. reactivity characteristics towards 2,2?-dipyridyl disulfide of the thiol groups of papain, chymopapains A and B, and papaya peptidase A

1982 ◽  
Vol 1 (2) ◽  
pp. 119-139 ◽  
Author(s):  
Baldev S. Baines ◽  
Keith Brocklehurst
Keyword(s):  
Carica Papaya ◽  
Cysteine Proteinase ◽  
Thiol Groups ◽  
Isolation And Characterization ◽  
Dipyridyl Disulfide

scholarly journals Purification and characterization of a tetrameric α-macroglobulin proteinase inhibitor from the gastropod mollusc Biomphalaria glabrata

1996 ◽  
Vol 316 (3) ◽  
pp. 893-900 ◽  
Author(s):  
Randall C. BENDER ◽  
Christopher J. BAYNE
Keyword(s):  
Quaternary Structure ◽  
Proteinase Inhibitors ◽  
Cysteine Proteinase ◽  
Serine Proteinase ◽  
Biomphalaria Glabrata ◽  
Sedimentation Equilibrium ◽  
Flight Mass Spectrometry ◽  
Isolation And Characterization ◽  
Α2 Macroglobulin

The α-macroglobulin proteinase inhibitors (αMs) are a family of proteins with the unique ability to inhibit a broad spectrum of proteinases. Whereas monomeric, dimeric and tetrameric αMs have been identified in vertebrates, all invertebrate αMs characterized so far have been dimeric. This paper reports the isolation and characterization of a tetrameric αM from the tropical planorbid snail Biomphalaria glabrata. The sequence of 18 amino acids at the N-terminus indicates homology with other αMs. The subunit mass of approx. 200 kDa was determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and SDS/PAGE. The quaternary structure was determined by sedimentation equilibrium centrifugation and native pore-limit electrophoresis. Evidence for a thioester is provided by the fact that methylamine treatment prevents the autolytic cleavage of the snail αM subunit and results in the release of 4 mol of thiols per mol of snail αM. The snail αM inhibited the serine proteinase trypsin, the cysteine proteinase bromelain and the metalloproteinase thermolysin. The spectrum of proteinases inhibited, together with the demonstration of steric protection of the proteinase active site and a ‘slow to fast’ conformational change after reacting with trypsin, all suggest that the inhibitory mechanism of the snail αM is similar to the ‘trap mechanism’ of human α2-macroglobulin.

scholarly journals Characterization of papaya peptidase A as a cysteine proteinase of Carica papaya L. with active-centre properties that differ from those of papain by using 2,2′-dipyridyl disulphide and 4-chloro-7-nitrobenzofurazan as reactivity probes. Use of two-protonic-state electrophiles in the identification of catalytic-site thiol groups

1982 ◽  
Vol 205 (1) ◽  
pp. 205-211 ◽  
Author(s):  
B S Baines ◽  
K Brocklehurst
Keyword(s):  
Carica Papaya ◽  
Cysteine Proteinase ◽  
Thiol Group ◽  
Catalytic Site ◽  
Interactive System ◽  
Ionization State ◽  
Active Centre ◽  
Ph Values ◽  
Activity Loss

1. The proteinase papaya peptidase A, one of the major components of the latex of Carica papaya L., was shown to contain 1 thiol group per molecule; this thiol group is essential for catalytic activity and is part of the catalytic site. 2. The usefulness of two-protonic-state reactivity probes coupled with modification/activity-loss data in assigning a thiol group as an integral part of the catalytic site as against merely ‘essential’ for activity is discussed. 3. The active centre of papaya peptidase A was investigated by using 2,2′-dipyridyl disulphide and 4-chloro-7-nitrobenzofurazan as reactivity probes. The presence in the enzyme in weakly acidic media of an interactive system containing a nucleophile S atom (pKI3.9,pKII7.9) was demonstrated. 5. Papaya peptidase A resembles ficin (EC 3.4.22.3) and actinidin (the cysteine proteinase from Actinidin chinenis) in that it does not appear to possess a carboxy group able to influence the reactivity of the thiol group by change of ionization state at pH values of about 4, a situation that contrasts markedly with that which obtains in papain. 6. Implications of the results for possible variations in cysteine proteinase mechanism are discussed.

Isolation and characterization of gingivain, a cysteine proteinase from Porphyromonas gingivalis strain W83

1990 ◽  
Vol 18 (4) ◽  
pp. 578-579 ◽  
Author(s):  
HAROUN N. SHAH ◽  
SAHEER E. GHARBIA ◽  
DEVANAND KOWLESSUR ◽  
ELIZABETH WILKIE ◽  
KEITH BROCKLEHURST
Keyword(s):  
Porphyromonas Gingivalis ◽  
Cysteine Proteinase ◽  
Isolation And Characterization

scholarly journals Isolation and characterization of isocitrate lyase from a thermophilic Bacillus sp

1978 ◽  
Vol 173 (1) ◽  
pp. 165-177 ◽  
Author(s):  
R M Chell ◽  
T K Sundaram ◽  
A E Wilkinson
Keyword(s):  
Thermal Denaturation ◽  
Isocitrate Lyase ◽  
Homogeneous State ◽  
Thiol Groups ◽  
Thermophilic Bacillus ◽  
Relative Paucity ◽  
Salt Activation ◽  
Isolation And Characterization ◽  
Mesophilic Bacterium

Isocitrate lyase was isolated in homogeneous state from a thermophilic Bacillus. The enzyme has a mol.wt. of 180000 and a pI of 4.5 and contains threonine as the N-terminal residue. It resembles in size the cognate enzyme from the mesophilic bacterium Pseudomonas indigofera, but is smaller than the enzyme from the eukaryotic fungus Neurospora crassa. All three lyases are tetramers and similar in amino acid composition, but the thermophile enzyme is distinctive from its mesophilic coutnerparts in possessing a lower catalytic-centre activity, greater resistance to chemical and thermal denaturation and fewer thiol groups and in being strongly activated by salts. Salt activation, by 0.4M-KCl, is about 3-fold at 30 degrees C and pH 6.8 and weakens progressively as the temperature or pH is raised. The activation is probably due to a change in the enzyme conformation caused by the electrolyte modifying the interaction between charged groups or between hydrophobic groups in protein. The possible significance of the salt activation, of the relative paucity of thiol groups and of the greater resistance to chemical denaturants is discussed. Besides its effect on the Vmax., KCl produces large increases in the magnitude of several kinetic parameters. A rise in reaction temperature from 30 to 55 degrees C produces a somewhat similar result. In view of these peculiar features, the patterns of inhibition of enzyme activity by compounds such as succinate and phosphoenolpyruvate were examined at 30 and 55 degrees C in the presence and absence of KCl.

scholarly journals Isolation and characterization of a cDNA encoding a mammalian cathepsin L-like cysteine proteinase from Acanthamoeba healyi

2002 ◽  
Vol 40 (1) ◽  
pp. 17 ◽  
Author(s):  
Yeon-Chul Hong ◽  
Mi-Yul Hwang ◽  
Ho-Cheol Yun ◽  
Hak-Sun Yu ◽  
Hyun-Hee Kong ◽  
...  
Keyword(s):  
Cysteine Proteinase ◽  
Cathepsin L ◽  
Isolation And Characterization

Isolation and characterization of a ‘quinone-trapping’ substance from a crude Carica papaya protein preparation

1998 ◽  
Vol 33 (3) ◽  
pp. 285-296 ◽  
Author(s):  
Florence Richard-Forget ◽  
Muriel Cerny ◽  
Nina Fayad ◽  
Thierry Saunier ◽  
Patrick Varoquaux
Keyword(s):  
Carica Papaya ◽  
Protein Preparation ◽  
Isolation And Characterization
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