Localization of the aspartic acid residue present in the active center of porcine pepsin

1973 ◽  
Vol 9 (4) ◽  
pp. 540-541
Author(s):  
Ya. F. Kovalishin ◽  
V. I. Ostoslavskaya ◽  
V. M. Stepanov
1971 ◽  
Vol 123 (1) ◽  
pp. 75-82 ◽  
Author(s):  
J. Kay ◽  
A. P. Ryle

Porcine pepsin C is inactivated rapidly and irreversibly by diazoacetyl-dl-norleucine methyl ester in the presence of cupric ions at pH values above 4.5. The inactivation is specific in that complete inactivation accompanies the incorporation of 1mol of inhibitor residue/mol of enzyme and evidence has been obtained to suggest that the reaction occurs with an active site residue. The site of reaction is the β-carboxyl group of an aspartic acid residue in the sequence Ile-Val-Asp-Thr. This sequence is identical with the active-site sequence in pepsin and the significance of this in terms of the different activities of the two enzymes is discussed.


1971 ◽  
Vol 124 (4) ◽  
pp. 673-676 ◽  
Author(s):  
Patricia A. Meitner

The specific inhibitor, N-diazoacetylnorleucine methyl ester reacts stoicheiometrically with bovine pepsin resulting in a simultaneous loss of all enzymic activity. A peptide containing a modified aspartyl group was isolated from bovine pepsin labelled with 14C-labelled inhibitor. The aspartic acid residue is presumed to be part of the active centre and is in the same heptapeptide sequence as in porcine pepsin: Ile-Val-Asp-Thr-Gly-Thr-Ser.


1994 ◽  
Vol 269 (18) ◽  
pp. 13680-13684
Author(s):  
A. Zlotnick ◽  
V.S. Reddy ◽  
R. Dasgupta ◽  
A. Schneemann ◽  
W.J. Ray ◽  
...  

1994 ◽  
Vol 301 (2) ◽  
pp. 577-583 ◽  
Author(s):  
K Oda ◽  
J Cheng ◽  
T Saku ◽  
N Takami ◽  
M Sohda ◽  
...  

Placental alkaline phosphatase (PLAP) is initially synthesized as a precursor (proPLAP) with a C-terminal extension. We constructed a recombinant cDNA which encodes a chimeric protein (alpha GL-PLAP) comprising rat alpha 2u-globulin (alpha GL) and the C-terminal extension of PLAP. Two molecular species (25 kDa and 22 kDa) were expressed in the COS-1 cell transfected with the cDNA for alpha GL-PLAP. Only the 22 kDa form was labelled with both [3H]stearic acid and [3H]ethanolamine. Upon digestion with phosphatidylinositol-specific phospholipase C the 22 kDa form was released into the medium, indicating that this form is anchored on the cell surface via glycosylphosphatidylinositol (GPI). A specific IgG raised against a C-terminal nonapeptide of proPLAP precipitated the 25 kDa form but not the 22 kDa form, suggesting that the 25 kDa form is a precursor retaining the C-terminal propeptide. When a mutant alpha GL-PLAP, in which the aspartic acid residue is replaced with tryptophan at a putative cleavage/attachment site, was expressed in COS-1 cells, the 25 kDa precursor was the only form found inside the cell and retained in the endoplasmic reticulum, as judged by immunofluorescence microscopy. In vitro translation programmed with mRNAs coding for the wild-type and mutant forms of alpha GL-PLAP demonstrated that the C-terminal propeptide was cleaved from the wild-type chimeric protein, but not from the mutant one. This gave rise to the 22 kDa form attached with a GPI anchor, suggesting that GPI is covalently linked to the aspartic acid residue (Asp159) of alpha GL-PLAP. Taken together, these results indicate that the C-terminal propeptide of PLAP functions as a signal to render alpha GL a GPI-linked membrane protein in vitro and in vivo in cultured cells, and that the chimeric protein constructed in this study may be useful for elucidating the mechanism underlying the cleavage of the propeptide and attachment of GPI, which occur in the endoplasmic reticulum.


Biochemistry ◽  
1993 ◽  
Vol 32 (29) ◽  
pp. 7526-7530 ◽  
Author(s):  
John E. Ladbury ◽  
Richard Wynn ◽  
Homme W. Hellinga ◽  
Julian M. Sturtevant

1991 ◽  
Vol 276 (2) ◽  
pp. 401-404 ◽  
Author(s):  
H M Lim ◽  
R K Iyer ◽  
J J Pène

An amino acid residue functioning as a general base has been proposed to assist in the hydrolysis of beta-lactam antibiotics by the zinc-containing Bacillus cereus beta-lactamase II [Bicknell & Waley (1985) Biochemistry 24, 6876-6887]. Oligonucleotide-directed mutagenesis of cloned Bacillus cereus 5/B/6 beta-lactamase II was used in an ‘in vivo’ study to investigate the role of carboxy-group-containing amino acids near the active site of the enzyme. Substitution of asparagine for the wild-type aspartic acid residue at position 81 resulted in fully functional enzyme. An aspartic acid residue at position 90 is essential for beta-lactamase II to confer any detectable ampicillin and cephalosporin C resistance to Escherichia coli. Conversion of Asp90 into Asn90 or Glu90 lead to the synthesis of inactive enzyme, suggesting that the spatial position of the beta-carboxy group of Asp90 is critical for enzyme function.


1969 ◽  
Vol 113 (2) ◽  
pp. 377-386 ◽  
Author(s):  
R. S. Bayliss ◽  
J. R. Knowles ◽  
Grith B. Wybrandt

Pepsin reacts stoicheiometrically with the active-site-directed irreversible inhibitor N-diazoacetyl-l-phenylalanine methyl ester, with concomitant loss of all proteolytic and peptidolytic activity. The reagent esterifies a unique aspartic acid residue in pepsin, which is in the sequence:Ile-Val-Asp-Thr-Gly-Thr-Ser


1974 ◽  
Vol 52 (11) ◽  
pp. 1018-1023 ◽  
Author(s):  
G. Mains ◽  
T. Hofmann

Penicillopepsin was fully inactivated by the pepsin inhibitor 1,2-epoxy-3-(p-nitrophenoxy) propane, and 1.3 ± 0.3 mol of reagent became associated with each mole of protein. Inactivation was more rapid at pH 3.0 than at pH 6.0. Approximately 1 equivalent of the bound reagent was esterified to an aspartic acid side chain. Enzyme previously inactivated with diazoacetylnorleucine methyl ester did not react with the epoxide; and enzyme that was first inactivated with the epoxide did not react with the diazo inhibitor. The results add further evidence for the enzymatic similarity of porcine pepsin and penicillopepsin.


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