Enhancing the Catalytic Activity of MOF‐808 Towards Peptide Bond Hydrolysis through Synthetic Modulations

The microspheres constituted by proteinoids synthesized from Fox’s simulation experiments. They had peptide bond structure and weak catalysis, as well as proliferated themselves. Such microspheres were believed the models for primitive life. Due to lack of metabolism and self-reproduction, the microspheres could not meet requirements of life. Thus, how microspheres could evolved into primitive life remain unsolved mysteries. The microspheres were supposed a dissipative structure and the processes of absorption and hydrolysis could be balanced to maintain their stability by consuming proteinoid. Proteinoid molecules differed in their life spans, which were mainly determined by their multi-space structures. Consequently, molecule selection and retention could occur spontaneously in microspheres and lead to a more organized and stabilized structure of the whole microsphere with time through dissipative process. More complex chain network of chemical reactions could happen in microspheres because the proteinoid with complex, ordered multi-space structure and relatively high catalytic activity would retain. In such microspheres, nucleotides could produce and further aggregate into RNA. The synthesis of real proteins could take place with RNA as the template catalyzed by proteinoids or RNA inside microspheres. When template-based protein molecules replaced the proteinoid inside the microspheres, a protein-based self-catalyzed network of chemical reactions could take place. It is plausible if Fox’s proteinoids microspheres is to dawn on a dissipative structure, then molecule selection could occur spontaneously by “dissipative” proteinoids, and the microspheres would acquire catalytic activity due to preserved the proteinoid with a large molecular weight and relatively complex and ordered multi-space structure, and relatively high catalytic activity. Thus the microspheres would spontaneously go to self-organizing, and evolve into primitive life.

Download Full-text

The conformation around the peptide bond between the P1- and P2-positions is important for catalytic activity of some proline-specific proteases

Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology ◽

10.1016/0167-4838(83)90261-3 ◽

1983 ◽

Vol 742 (3) ◽

pp. 452-462 ◽

Cited By ~ 60

Author(s):

Gunter Fischer ◽

Jochen Heins ◽

Alfred Barth

Keyword(s):

Catalytic Activity ◽

Peptide Bond

Download Full-text

Chemical Synthesis of an Enzyme Containing an Artificial Catalytic Apparatus

Australian Journal of Chemistry ◽

10.1071/ch19460 ◽

2020 ◽

Vol 73 (4) ◽

pp. 321

Author(s):

Vladimir Torbeev ◽

Stephen B. H. Kent

Keyword(s):

Catalytic Activity ◽

Chemical Synthesis ◽

Enzyme Catalysis ◽

Polypeptide Chain ◽

Peptide Bond ◽

Enzyme Molecule ◽

Peptide Substrates ◽

Unique Approach ◽

Hiv 1 ◽

Residue Polypeptide

With the goal of investigating electronic aspects of the catalysis of peptide bond hydrolysis, an analogue of HIV-1 protease was designed in which a non-peptide hydroxy-isoquinolinone artificial catalytic apparatus replaced the conserved Asp25–Thr26–Gly27 sequence in each 99-residue polypeptide chain of the homodimeric enzyme molecule. The enzyme analogue was prepared by total chemical synthesis and had detectable catalytic activity on known HIV-1 protease peptide substrates. Compared with uncatalyzed hydrolysis, the analogue enzyme increased the rate of peptide bond hydrolysis by ∼108-fold. Extensions of this unique approach to the study of enzyme catalysis in HIV-1 protease are discussed.

Download Full-text

Substitution of histidine-137 by glutamine abolishes the catalytic activity of the ribosome-inactivating protein α-sarcin

Biochemical Journal ◽

10.1042/bj3090581 ◽

1995 ◽

Vol 309 (2) ◽

pp. 581-586 ◽

Cited By ~ 27

Author(s):

J Lacadena ◽

J M Mancheño ◽

A Martinez-Ruiz ◽

A Martínez del Pozo ◽

M Gasset ◽

...

Keyword(s):

Catalytic Activity ◽

Sequence Similarity ◽

Protein Biosynthesis ◽

Fluorescence Emission ◽

Peptide Bond ◽

Wild Type ◽

Fluorescence Emission Spectra ◽

Phosphodiester Bond ◽

Type Protein ◽

Wild Type Protein

The alpha-sarcin cytotoxin is an extracellular fungal protein that inhibits protein biosynthesis by specifically cleaving one phosphodiester bond of the 28 S rRNA. The His137 residue of alpha-sarcin is suggested to be involved in the catalytic activity of this protein, based on the observed sequence similarity with some fungal ribonucleases. Replacement of this residue by Gln (H137Q mutant variant of alpha-sarcin) abolishes the ribonuclease activity of the protein. This has been demonstrated for an homogeneous preparation of the H137Q alpha-sarcin by measuring its effect against both intact rabbit ribosomes and the homopolymer poly(A). The conformation of H137Q alpha-sarcin is highly similar to that of the wild-type protein, which has been analysed by CD and fluorescence spectroscopy. Both H137Q and wild-type alpha-sarcin exhibit identical CD spectra in the peptide-bond region, indicating that no changes at the level of the secondary structure are produced upon mutation. Only minor differences are observed in both near-UV CD and fluorescence emission spectra in comparison to those of the wild-type protein. Moreover, H137Q alpha-sarcin interacts with phospholipid vesicles, promoting the same effects as the native cytotoxin. Therefore, we propose that His137 is part of the ribonucleolytic active site of the cytotoxin alpha-sarcin.

Download Full-text

High resolution electron microscopy of lanthanum phosphate crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108519 ◽

1978 ◽

Vol 36 (1) ◽

pp. 274-275

Author(s):

J. C. Wheatley ◽

J. M. Cowley

Keyword(s):

Electron Microscopy ◽

Catalytic Activity ◽

High Resolution ◽

Petroleum Industry ◽

High Resolution Electron Microscopy ◽

Lanthanum Phosphate ◽

Good Catalyst ◽

Resolution Electron ◽

Good Catalytic Activity ◽

Physical And Chemical

Rare-earth phosphates are of particular interest because of their catalytic properties associated with the hydrolysis of many aromatic chlorides in the petroleum industry. Lanthanum phosphates (LaPO4) which have been doped with small amounts of copper have shown increased catalytic activity (1). However the physical and chemical characteristics of the samples leading to good catalytic activity are not known.Many catalysts are amorphous and thus do not easily lend themselves to methods of investigation which would include electron microscopy. However, the LaPO4, crystals are quite suitable samples for high resolution techniques.The samples used were obtained from William L. Kehl of Gulf Research and Development Company. The electron microscopy was carried out on a JEOL JEM-100B which had been modified for high resolution microscopy (2). Standard high resolution techniques were employed. Three different sample types were observed: 669A-1-5-7 (poor catalyst), H-L-2 (good catalyst) and 27-011 (good catalyst).

Download Full-text

Role of the Small (40S) Subunits in the Structure of the Interface of Eukaryotic Ribosomes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600002427 ◽

1980 ◽

Vol 38 ◽

pp. 548-549

Author(s):

M. Boublik ◽

N. Robakis ◽

W. Hellmann ◽

F. Jenkins

Keyword(s):

Structural Similarity ◽

High Resolution Electron Microscopy ◽

Peptide Bond ◽

Uranyl Acetate ◽

Mutual Orientation ◽

Mutual Position ◽

Peptide Bond Formation ◽

Resolution Electron ◽

Direct Technique ◽

Structural Details

Ribosomes are ribonucleoprotein particles which process the genetic information coded in mRNA into protein synthesis. The analogy in function and composition of ribosomes from various sources, both prokaryotic and eukaryo-tic, imply a structural similarity. At present, high resolution electron microscopy is the most direct technique with a potential to resolve the extent of the structural homology of ribosomal particles at a macromolecular level. The structure of ribosomes is highly complex as a result of the large number of their constituents. In general, 80S eukaryotic monosomes consist of two uneven subunits - large (60S) and small (40S) - accomodating four different RNAs and approximately 80 different proteins. Mutual orientation of both subunits on the monosome is of particular interest because it determines the interface, the supposed site of interactions of ribosomes with other macro-molecules involved in peptide bond formation. Since entrapping of the contrasting solution (0.5% aqueous uranyl acetate) obscures all structural details in the interface, information on its architecture is limited to an indirect reconstruction based on the established 3-D structure of both sub-units and their mutual position after association.

Download Full-text

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

Catalysis Science & Technology ◽

10.1039/c8cy02291g ◽

2019 ◽

Vol 9 (3) ◽

pp. 811-821 ◽

Cited By ~ 7

Author(s):

Zhao-Meng Wang ◽

Li-Juan Liu ◽

Bo Xiang ◽

Yue Wang ◽

Ya-Jing Lyu ◽

...

Keyword(s):

Catalytic Activity ◽

Active Sites ◽

Aerobic Oxidation ◽

Catalytic Performance ◽

Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

Download Full-text

Effect of Fibrin-Like Stimulators on the Activation of Plasminogen by Tissue-Type Plasminogen Activator (t-PA) - Studies with Active Site Mutagenized Plasminogen and Plasmin Resistant t-PA

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647254 ◽

1990 ◽

Vol 64 (01) ◽

pp. 061-068 ◽

Cited By ~ 19

Author(s):

H R Lijnen ◽

B Van Hoet ◽

F De Cock ◽

D Collen

Keyword(s):

Active Site ◽

Peptide Bond ◽

Tissue Type ◽

Wild Type ◽

Single Chain ◽

Plasmin Activity ◽

Soluble Fibrin ◽

Type Plasminogen Activator ◽

Presence And Absence ◽

Chain Form

SummaryThe activation of plasminogen by t-PA was measured in the presence and absence of fibrin stimulation, using natural human plasminogen (nPlg) and rPlg-Ala740, a recombinant plasminogen with the active site Ser740 mutagenaed to Ala. Recombinant wild type t-PA (rt-PA) was used as well as rt-PA -Glul275, a recombinant single chain t-PA in which the Arg of the plasmin sensitiv e Arg275- Ile276 peptide bond was substituted with Glu. Conversion of 125I-labeled single chain plasminogen to two-chain plasmin by wild-type or mutant t-PA, was quantitated by SDS gel electrophoresis and radioisotope counting of gel slices, and expressed as initial activation rates (v0 in pM s−1) per 1 μM enzyme. In the absence of fibrin stimulation, the vs for the activation of nPlg and rPlg-Ala740 with the single chain forms of both t-PAs were comparable (0.6 to 2.7 pM s−1) but were lower than with the corresponding two-chain forms (5.3 to 23 pM s−1). In the presence of 1 μM soluble fibrin monomer (desAAfibrin), the v0 for nPlg and rPlg-Ala740 by single chain rt-PA was also comparable (24 and, 33 pM s-1 respectively), whereas with 1 pM CNBr-digested fibrinogen, the vs for nPlg with single chain rt-PA was about 20-fold higher than that of rPlg-Ala740 (135 and 7.5 pM s−1 respectively). In contrast, the vs for nPlg and rPlg-Ala740 by single chain rt-PA- G1u275, two-chain rt-PA-G1u275 or two-chain rt-PA were comparable in the presence of either desAAfibrin or CNBr-digested fibrinogen.These findings confirm and establish: 1) that single chain t-PA is an active enzyme both in the presence and absence of fibrin stimulator; 2) that, in a system devoid of plasmin activity (rPlg- Ala740), the two-chain form of t-PA is about L5 times more active than the single chain form in the absence of fibrin but equipotent in the presence of desAAfibrin; and 3) that the mechanism of stimulation of plasminogen activation with single chain t-PA by CNBr-digested fibrinogen is different from that by soluble fibrin.

Download Full-text

Prolonged Expression of Procoagulant Activity of Human Platelets Degranulated by Thrombin

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649855 ◽

1995 ◽

Vol 74 (03) ◽

pp. 958-961 ◽

Cited By ~ 6

Author(s):

Raelene L Kinlough-Rathbone ◽

Dennis W Perry

Keyword(s):

Catalytic Activity ◽

Thrombus Formation ◽

Annexin V ◽

Human Platelets ◽

Procoagulant Activity ◽

Prothrombinase Complex ◽

Arterial Thrombus ◽

Flowing Blood

SummaryPlatelets are exposed to thrombin when they take part in arterial thrombus formation, and they may return to the circulation when they are freed by fibrinolysis and dislodged by flowing blood. Thrombin causes the expression of procoagulant activity on platelets, and if this activity persists, the recirculating platelets may contribute to subsequent thrombosis. We have developed techniques to degranulate human platelets by treatment with thrombin, and recover them as single, discrete platelets that aggregate in response to both weak and strong agonists. In the present study we examined the duration of procoagulant activity on the surface of thrombin-degranulated platelets by two methods: a prothrombinase assay, and the binding of 125I-labeled annexin. Control platelets generated 0.9 ± 0.4 U thrombin per 107 platelets in 15 min. Suspensions of thrombin-degranulated platelets formed 5.4 ± 0.1 U thrombin per 107 platelets in this time. Binding of 125I-annexin V was also greater with thrombin-treated platelets than with control platelets (controls: 1.7 ±0.1 ng annexin/107 platelets; thrombin-degranulated platelets: 6.8 ± 0.2 ng annexin/107 platelets). With thrombin-degranulated platelets, increased procoagulant activity and annexin binding persisted for at least 4 h after degranulation and resuspension, indicating that the catalytic activity for the prothrombinase complex is not reversed during this time. These platelets maintained their ability to aggregate for 4 h, even in response to the weak agonist, ADP. Thus, platelets that have taken part in thrombus formation and returned to the circulation may contribute to the promotion of further thrombotic events because of the persistence of procoagulant activity on their surface.

Download Full-text