scholarly journals The effect of proteinases on phenylalanine ammonia-lyase from the yeast Rhodotorula glutinis

1981 ◽  
Vol 199 (3) ◽  
pp. 715-723 ◽  
Author(s):  
H J Gilbert ◽  
G W Jack
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Bond Cleavage ◽  
Rhodotorula Glutinis ◽  
Peptide Bond ◽  
Enzymic Activity ◽  
Duodenal Juice ◽  
Prosthetic Group ◽  
Prolonged Incubation ◽  
Peptide Bond Cleavage ◽  
Site Binding

Phenylalanine ammonia-lyase (EC 4.3.1.5) of the yeast Rhodotorula glutinis was rapidly inactivated by duodenal juice. It was susceptible to chymotrypsin and subtilisin and to a lesser extent trypsin. Initial proteolysis of the enzyme by chymotrypsin and trypsin resulted in cleavage of the monomeric subunit (75 000 Mr) into a large (65 000 Mr) and a small (10 000 Mr) peptide. The small peptide was rapidly degraded. The 65 000-Mr fragment was resistant to prolonged incubation with chymotrypsin, but was degraded by trypsin under the same conditions. Phenylalanine ammonia-lyase was cleaved into several polypeptides by subtilisin, the 65 000-Mr peptide being totally absent. The N-terminal region of the enzyme was contained in the 65 000-Mr fragment, as was the dehydroalanine moiety, the prosthetic group. Active-site-binding ligands protect the enzyme from inactivation by the three proteinases, and peptide-bond cleavage by trypsin and chymotrypsin. Several chemical modifications were performed on phenylalanine ammonia-lyase. Some decreased its antigenicity, and ethyl acetimidate decreased the rate of degradation of the 65 000-Mr peptide by trypsin. The modification did not protect the enzyme from proteolytic inactivation of the enzymic activity. These observations are discussed in terms of the structure of phenylalanine ammonia-lyase and site of action of the proteinases.

scholarly journals Specific proteolytic modification of creatine kinase isoenzymes. Implication of C-terminal involvement in enzymic activity but not in subunit-subunit recognition

1986 ◽  
Vol 233 (1) ◽  
pp. 51-56 ◽  
Author(s):  
H G Lebherz ◽  
T Burke ◽  
J E Shackelford ◽  
J E Strickler ◽  
K J Wilson
Keyword(s):  
Creatine Kinase ◽  
Amino Acid ◽  
Bond Cleavage ◽  
Peptide Bond ◽  
Cysteine Residue ◽  
Enzymic Activity ◽  
Proteinase K ◽  
Peptide Bond Cleavage ◽  
Active Site Cysteine

We are using the isoenzymes of creatine kinase (CK) to investigate the effect of specific proteolytic modification on the abilities of enzyme subunits to establish precise subunit-subunit recognition in vitro. Previous work by others has shown that treatment of the MM isoenzyme of rabbit CK with Proteinase K results in a specific proteolytic modification and inactivation of the enzyme. In the present work, we show that both the MM and BB isoenzymes of chicken CK are also specifically modified by Proteinase K, resulting in over 98% loss of catalytic activity and approx. 10% decreases in subunit molecular masses of the enzymes. Similar reactions appear to occur when the isoenzymes are treated with Pronase E. Limited amino acid sequence analysis of intact and Proteinase K-modified MM-CK suggests that the proteolytic modification results from a single peptide-bond cleavage occurring between alanine residues 328 and 329, about 50 amino acid residues from the C-terminal end; the active-site cysteine residue was recovered in the large protein fragment of modified M-CK subunits. Proteolytically modified M-CK and B-CK subunits were able to refold and reassociate into dimeric structures after treatment with high concentrations of LiCl and at low pH. Thus the proteolytically modified CK subunits retain their ability to refold and to establish precise subunit-subunit recognition in vitro.

scholarly journals Serine protease dynamics revealed by NMR analysis of the thrombin-thrombomodulin complex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Riley B. Peacock ◽  
Taylor McGrann ◽  
Marco Tonelli ◽  
Elizabeth A. Komives
Keyword(s):  
Active Site ◽  
Serine Proteases ◽  
Protein C ◽  
Catalytic Mechanism ◽  
Bond Cleavage ◽  
Peptide Bond ◽  
Peptide Bond Cleavage ◽  
Exchange Mass Spectrometry ◽  
Catalytically Active ◽  
Hydrogen Deuterium

AbstractSerine proteases catalyze a multi-step covalent catalytic mechanism of peptide bond cleavage. It has long been assumed that serine proteases including thrombin carry-out catalysis without significant conformational rearrangement of their stable two-β-barrel structure. We present nuclear magnetic resonance (NMR) and hydrogen deuterium exchange mass spectrometry (HDX-MS) experiments on the thrombin-thrombomodulin (TM) complex. Thrombin promotes procoagulative fibrinogen cleavage when fibrinogen engages both the anion binding exosite 1 (ABE1) and the active site. It is thought that TM promotes cleavage of protein C by engaging ABE1 in a similar manner as fibrinogen. Thus, the thrombin-TM complex may represent the catalytically active, ABE1-engaged thrombin. Compared to apo- and active site inhibited-thrombin, we show that thrombin-TM has reduced μs-ms dynamics in the substrate binding (S1) pocket consistent with its known acceleration of protein C binding. Thrombin-TM has increased μs-ms dynamics in a β-strand connecting the TM binding site to the catalytic aspartate. Finally, thrombin-TM had doublet peaks indicative of dynamics that are slow on the NMR timescale in residues along the interface between the two β-barrels. Such dynamics may be responsible for facilitating the N-terminal product release and water molecule entry that are required for hydrolysis of the acyl-enzyme intermediate.

Activation of Bovine Factor V by Thrombin and A Protease From Russell's Viper Venom (RVV)

1979 ◽  
Author(s):  
M.J. Lindhout ◽  
C. M. Jackson
Keyword(s):  
Bond Cleavage ◽  
Peptide Bond ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Factor V ◽  
Peptide Bond Cleavage ◽  
Prothrombinase Complex ◽  
Factor Va ◽  
Activation Products ◽  
Ca Oxalate

In order to understand the function of activated factor V in the prothrombinase complex, we isolated the activation products obtained by action of thrombin and RVV-V on factor V and studied their functional properties. Factor V isolated from plasma by means of ion-exchange chromatography, a Ca-oxalate adsorption step and gelfiltration was homogenous in SDS-gelelectrophoresis (apparent MW 360,000, with and without reduction). Increase in factor V activity upon action by RVV-V is correlated with a single peptide bond cleavage, resulting in a 270,000 dalton and a 80,000 dalton component. Additional proteolysis of factor Va(RVV/V)’ by thrombin results in a further cleavage of the high MW component into peptides with MW's of 72,000, 94,000 and about 150,000 without a furth~r increase in factor V activity. Whereas none of the isolated peptides reveal factor Va activity, activity would be generated by a recombination in the presence of Ca2+ of the 94,000 MW or 270,000 MW component with the 80,000 component. Action of thrombin alone on factor V results in peptides of MW 72,000, 80,000, 94,000 and a peptide very rich in carbohydrate with an apparent MW of 150,000.

Demasking kinetics of peptide bond cleavage for whey protein isolate hydrolysed by Bacillus licheniformis protease

2016 ◽  
Vol 133 ◽  
pp. S426-S431 ◽  
Author(s):  
Mikhail M. Vorob’ev ◽  
Claire I. Butré ◽  
Stefano Sforza ◽  
Peter A. Wierenga ◽  
Harry Gruppen
Keyword(s):  
Whey Protein ◽  
Bacillus Licheniformis ◽  
Bond Cleavage ◽  
Peptide Bond ◽  
Whey Protein Isolate ◽  
Protein Isolate ◽  
Peptide Bond Cleavage ◽  
Kinetics Of

ChemInform Abstract: Unusual Peptide Bond Cleavage Reactions During Acidolytic Deprotection Reactions.

ChemInform ◽  
2010 ◽  
Vol 24 (28) ◽  
pp. no-no
Author(s):  
J. R. SPENCER ◽  
N. G. J. DELAET ◽  
A. TOY-PALMER ◽  
V. V. ANTONENKO ◽  
M. GOODMAN
Keyword(s):  
Bond Cleavage ◽  
Peptide Bond ◽  
Peptide Bond Cleavage ◽  
Cleavage Reactions
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