Amino-terminal groups in zymogen activation: effect of nitrous acid on pepsin

1969 ◽  
Vol 47 (12) ◽  
pp. 1099-1101 ◽  
Author(s):  
T. Hofmann
Keyword(s):  
Nitrous Acid ◽  
Lysine Residue ◽  
Amino Group ◽  
Serine Proteinases ◽  
Zymogen Activation ◽  
Activation Effect ◽  
Amino Terminal ◽  
Tryptophan Residues ◽  
Terminal Amino ◽  
Isoleucine Residue

Nitrous acid rapidly deaminates the N-terminal isoleucine residue of pepsin. The enzyme retains more than 60% of its activity. The loss of 30–40% activity can be ascribed to the reaction of two tryptophan residues with nitrous acid. The single lysine residue is also deaminated. These results are in contrast to those obtained with serine proteinases where nitrous acid causes inactivation due to the deamination of the N-terminal amino group.

Inactivation of bovine thrombin by nitrous acid

1970 ◽  
Vol 48 (4) ◽  
pp. 432-437 ◽  
Author(s):  
S. Magnusson ◽  
T. Hofmann
Keyword(s):  
Ethyl Ester ◽  
Esterase Activity ◽  
Nitrous Acid ◽  
Initial Rate ◽  
Serine Proteinases ◽  
Bovine Thrombin ◽  
Partial Protection ◽  
Isoleucine Residue ◽  
Full Protection ◽  
Prothrombin Activation

Bovine thrombin is rapidly inactivated by nitrous acid at pH 4.35 and 0°. The clotting activity falls off more rapidly than the activity towards N-benzoylarginine ethyl ester. The loss of esterase activity parallels the loss of the N-terminal isoleucine residue. N-Benzoylarginine ethyl ester gives almost full protection of the esterase activity and the N-terminal isoleucine, but only partial protection of the clotting activity. These results suggest strongly that this residue is essential for activity and indicate that thrombin resembles the pancreatic serine proteinases in this respect. The initial rate of inactivation of thrombin by nitrous acid is higher than that of trypsin, and considerably higher than that of elastase and α-chymotrypsin under the same conditions, suggesting that the N-terminal residue is more readily accessible to the reagent. The experiments strengthen the hypothesis that all mechanisms of prothrombin activation are proteolytic and suggest that they involve the liberation of the essential N-terminal isoleucine.

Reaction of metallic nitrilotriacetates with histamine

1969 ◽  
Vol 47 (8) ◽  
pp. 1269-1273 ◽  
Author(s):  
A. L. Beauchamp ◽  
J. Israeli ◽  
H. Saulnier
Keyword(s):  
Potentiometric Titration ◽  
Formation Constants ◽  
Amino Group ◽  
Mixed Complex ◽  
Ph Values ◽  
Titration Curves ◽  
Terminal Amino ◽  
Complex Ion

Cu(II), Ni(II), Co(II), and Zn(II) nitrilotriacetates (MeX−) react with histamine nitrate (LH+) to form a protonated mixed complex MeXLH where the metal appears to be bound only to the tertiary imidazolic nitrogen of histaminium ion. At higher pH values the proton dissociates to yield a mixed complex ion MeXL− in which both the imidazolic nitrogen and the terminal amino group are coordinated. The formation constants of these species were calculated from the potentiometric titration curves.

Synthesis of three Salmonella epitopes for biosensor studies of carbohydrate–antibody interactions

2002 ◽  
Vol 80 (8) ◽  
pp. 1131-1140 ◽  
Author(s):  
Henry N Yu ◽  
Chang-Chun Ling ◽  
David R Bundle
Keyword(s):  
Key Words ◽  
Self Assembled Monolayers ◽  
Antigenic Determinants ◽  
Amino Group ◽  
Assembled Monolayers ◽  
Construction Of Self ◽  
Terminal Amino ◽  
Salmonella Serotypes ◽  
O Antigens ◽  
Antibody Interactions

Disaccharides 1-3 corresponding to the antigenic determinants of Salmonella serotypes A, B, and D1 were synthesized in a form suited for use in biosensors. The disaccharide determinants each contain a unique 3,6-dideoxyhexose, namely abequose (3,6-dideoxy-D-xylo-hexose), paratose (3,6-dideoxy-D-ribohexose), and tyvelose (3,6-dideoxy-D-arabino-hexose), are α-linked to the 3-position of D-mannopyranose. The disaccharides were further derivatized with a linear aglycon that has a terminal amino group, and can be readily coupled to pertinent chains carrying a terminal thiol for the construction of self-assembled monolayers (SAMs). Efficient routes that employed a single 3,6-dideoxygenation step were developed for the synthesis of paratoside 15 and tyveloside 22.Key words: Salmonella O-antigens, lipopolysaccharide, abequose, paratose, tyvelose, 3,6-dideoxyhexose, deoxygenation, glycoside tethers, immobilization via pentenyl glycosides.

N-Terminal amino acid sequence of rat tonin: homology with serine proteases

1978 ◽  
Vol 56 (9) ◽  
pp. 920-925 ◽  
Author(s):  
N. G. Seidah ◽  
R. Routhier ◽  
M. Caron ◽  
M. Chrétien ◽  
S. Demassieux ◽  
...  
Keyword(s):  
Serine Proteases ◽  
Terminal Sequence ◽  
Renin Substrate ◽  
Amino Terminal ◽  
Single Polypeptide Chain ◽  
Serine Protease Family ◽  
Terminal Amino ◽  
Single Polypeptide ◽  
Carboxy Terminal ◽  
Amino Terminal Sequence

In this paper, we present the amino-terminal sequence of rat tonin, an endopeptidase responsible for the conversion of angiotensinogen, the tetradecapeptide renin substrate, or angiotensin I to angiotensin II. It is shown that isoleucine and proline occupy the amino- and carboxy-terminal residues respectively. The N-terminal sequence analysis permitted the identification of 34 out of the first 40 residue s of the single polypeptide chain composed of 272 amino acids. The se results showed an extensive homology with the sequence of many serine proteases of the trypsin–chymotrypsin family. This information, coupled with the slow inhibition of tonin by diisopropylfluorophosphate, classified this enzyme as a selective endopeptidase of the active serine protease family.

scholarly journals Specificity of RNA Binding by CPEB: Requirement for RNA Recognition Motifs and a Novel Zinc Finger

1998 ◽  
Vol 18 (2) ◽  
pp. 685-693 ◽  
Author(s):  
Laura E. Hake ◽  
Raul Mendez ◽  
Joel D. Richter
Keyword(s):  
Zinc Finger ◽  
Rna Binding ◽  
Rna Recognition ◽  
Cytoplasmic Polyadenylation ◽  
Functional Motif ◽  
Rna Recognition Motifs ◽  
Amino Terminal ◽  
Terminal Amino ◽  
Maternal Mrnas ◽  
Recognition Motifs

ABSTRACT CPEB is an RNA binding protein that interacts with the maturation-type cytoplasmic polyadenylation element (CPE) (consensus UUUUUAU) to promote polyadenylation and translational activation of maternal mRNAs in Xenopus laevis. CPEB, which is conserved from mammals to invertebrates, is composed of three regions: an amino-terminal portion with no obvious functional motif, two RNA recognition motifs (RRMs), and a cysteine-histidine region that is reminiscent of a zinc finger. In this study, we investigated the physical properties of CPEB required for RNA binding. CPEB can interact with RNA as a monomer, and phosphorylation, which modifies the protein during oocyte maturation, has little effect on RNA binding. Deletion mutations of CPEB have been overexpressed inEscherichia coli and used in a series of RNA gel shift experiments. Although a full-length and a truncated CPEB that lacks 139 amino-terminal amino acids bind CPE-containing RNA avidly, proteins that have had either RRM deleted bind RNA much less efficiently. CPEB that has had the cysteine-histidine region deleted has no detectable capacity to bind RNA. Single alanine substitutions of specific cysteine or histidine residues within this region also abolish RNA binding, pointing to the importance of this highly conserved domain of the protein. Chelation of metal ions by 1,10-phenanthroline inhibits the ability of CPEB to bind RNA; however, RNA binding is restored if the reaction is supplemented with zinc. CPEB also binds other metals such as cobalt and cadmium, but these destroy RNA binding. These data indicate that the RRMs and a zinc finger region of CPEB are essential for RNA binding.

scholarly journals THE AMINO-TERMINAL AMINO ACIDS OF PAROTIN

1960 ◽  
Vol 7 (3) ◽  
pp. 175-180
Author(s):  
YUKIHO KUBOTA
Keyword(s):  
Amino Acids ◽  
Amino Terminal ◽  
Terminal Amino

scholarly journals New Histamine-Related Five-Membered N-Heterocycle Derivatives as Carbonic Anhydrase I Activators

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 545
Author(s):  
Niccolò Chiaramonte ◽  
Alessio Gabellini ◽  
Andrea Angeli ◽  
Gianluca Bartolucci ◽  
Laura Braconi ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Imidazole Ring ◽  
Aliphatic Chain ◽  
Amino Group ◽  
Carbonic Anhydrase I ◽  
Terminal Amino ◽  
Human Carbonic Anhydrase ◽  
New Compounds ◽  
Related Compounds ◽  
Micromolar Range

A series of histamine (HST)-related compounds were synthesized and tested for their activating properties on five physiologically relevant human Carbonic Anhydrase (hCA) isoforms (I, II, Va, VII and XIII). The imidazole ring of HST was replaced with different 5-membered heterocycles and the length of the aliphatic chain was varied. For the most interesting compounds some modifications on the terminal amino group were also performed. The most sensitive isoform to activation was hCA I (KA values in the low micromolar range), but surprisingly none of the new compounds displayed activity on hCA II. Some derivatives (1, 3a and 22) displayed an interesting selectivity for activating hCA I over hCA II, Va, VII and XIII.

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