Studies on the soluble and membrane-bound amino acid 2-naphthylamidases in pig and human epidermis

1. Membrane-bound (particulate) and soluble amino acid 2-naphthylamidases (EC 3.5.1.-) were present in subcellular fractions of epidermis from pig and human. 2. The particulate enzymes exhibited Michaelis-Menten kinetics, with Km 5.1x10(-5) (pig) and Km 7.3x10(-5)M (human) for the substrate L-leucine 2-naphthylamide. They were inhibited by puromycin and partially inhibited by EDTA. They did not require heavy metals and were not inhibited by thiol-group-blocking agents. Their pH optima were 7.0 (human) and 6.6 (pig). The particulate enzyme from pig epidermis retained 50% activity after 30 min at 70 degrees C. 3. The soluble amino acid 2-naphthylamidases gave sigmoidal curves for reaction velocity versus substrate concentration, and the kinetic data suggested that there was positive co-operativity between binding sites. This co-operativity was lost after treatment with 0.1mM-p-hydroxymercuribenzoate and the enzymes showed first-order kinetics at low substrate concentrations. The soluble enzymes were inhibited by puromycin and by thiol-group-blocking agents and activated by dithiothreitol. They were inactivated above 60 degrees C and lost activity on storage, but this could be restored with dithiothreitol. 4. The amino acid 2-naphthylamidases of human epidermis were much more active (2.5 times) towards L-alanine 2-naphthylamide than towards the commonly used substrate L-leucine 2-naphthylamide. 5. The kinetics of both the solube and particulate enzymes from epidermis of some elderly patients with either diabetes or ischaemia showed some differences from the kinetics of enzymes from healthy epidermis from younger individuals.

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The effect of low concentrations of thiol-group-blocking agents on the outer membrane of frog skin

Biochimica et Biophysica Acta ◽

10.1016/0006-3002(62)90525-5 ◽

1962 ◽

Vol 56 ◽

pp. 42-48 ◽

Cited By ~ 10

Author(s):

K. Janáček

Keyword(s):

Outer Membrane ◽

Frog Skin ◽

Thiol Group ◽

Blocking Agents ◽

Low Concentrations ◽

Group Blocking

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Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

10.31221/osf.io/m9g7p ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Methyl Orange ◽

Solution Ph ◽

Vanadium Concentration ◽

Limiting Behavior ◽

First Order ◽

First Order Kinetics ◽

Ph Range ◽

Kinetic Pattern ◽

Triton X ◽

Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH < 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

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Purification and properties of D-amino acid dehydrogenase, an inducible membrane-bound iron-sulfur flavoenzyme from Escherichia coli B.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)85517-5 ◽

1980 ◽

Vol 255 (10) ◽

pp. 4487-4494

Author(s):

P.J. Olsiewski ◽

G.J. Kaczorowski ◽

C. Walsh

Keyword(s):

Escherichia Coli ◽

Amino Acid ◽

Acid Dehydrogenase ◽

Amino Acid Dehydrogenase ◽

Iron Sulfur ◽

Purification And Properties ◽

Membrane Bound ◽

Escherichia Coli B

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Measuring microtubule binding kinetics of membrane-bound kinesin motors using supported lipid bilayers

STAR Protocols ◽

10.1016/j.xpro.2021.100691 ◽

2021 ◽

Vol 2 (3) ◽

pp. 100691

Author(s):

Rui Jiang ◽

William O. Hancock

Keyword(s):

Lipid Bilayers ◽

Binding Kinetics ◽

Supported Lipid Bilayers ◽

Microtubule Binding ◽

Membrane Bound ◽

Kinetics Of

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Front Cover: A Single Second Shell Amino Acid Determines Affinity and Kinetics of Linagliptin Binding to Type 4 Dipeptidyl Peptidase and Fibroblast Activation Protein (ChemMedChem 4/2021)

ChemMedChem ◽

10.1002/cmdc.202100054 ◽

2021 ◽

Vol 16 (4) ◽

pp. 599-599

Author(s):

Gisela Schnapp ◽

Yvette Hoevels ◽

Remko A. Bakker ◽

Patrick Schreiner ◽

Thomas Klein ◽

...

Keyword(s):

Amino Acid ◽

Dipeptidyl Peptidase ◽

Fibroblast Activation Protein ◽

Front Cover ◽

Fibroblast Activation ◽

Kinetics Of

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Empirical Validation of a Biogas Plant Simulation Model and Analysis of Biogas Upgrading Potentials

Energies ◽

10.3390/en14092424 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2424

Author(s):

Jan Martin Zepter ◽

Jan Engelhardt ◽

Tatiana Gabderakhmanova ◽

Mattia Marinelli

Keyword(s):

Simulation Model ◽

Biogas Production ◽

Biogas Plant ◽

Raw Material ◽

Biogas Upgrading ◽

Integrated Energy Systems ◽

First Order Kinetics ◽

Biogas Plants ◽

Plant Simulation ◽

Kinetics Of

Biogas plants may support the transformation towards renewable-based and integrated energy systems by providing dispatchable co-generation as well as opportunities for biogas upgrading or power-to-X conversion. In this paper, a simulation model that comprises the main dynamics of the internal processes of a biogas plant is developed. Based on first-order kinetics of the anaerobic digestion process, the biogas production of an input feeding schedule of raw material can be estimated. The output of the plant in terms of electrical and thermal energy is validated against empirical data from a 3-MW biogas plant on the Danish island of Bornholm. The results show that the model provides an accurate representation of the processes within a biogas plant. The paper further provides insights on the functioning of the biogas plant on Bornholm as well as discusses upgrading potentials of biogas to biomethane at the plant from an energy perspective.

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Comparative Study of Chemical Stability of Two H1Antihistaminic Drugs, Terfenadine and ItsIn VivoMetabolite Fexofenadine, Using LC-UV Methods

Journal of Analytical Methods in Chemistry ◽

10.1155/2019/5790404 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10

Author(s):

Anna Gumieniczek ◽

Anna Berecka-Rycerz ◽

Rafał Pietraś ◽

Izabela Kozak ◽

Karolina Lejwoda ◽

...

Keyword(s):

Comparative Study ◽

Chemical Stability ◽

First Order ◽

First Order Kinetics ◽

Kinetics Of Degradation ◽

Effects Of Temperature ◽

High Doses ◽

Antihistaminic Drugs ◽

Kinetics Of

A comparative study of chemical stability of terfenadine (TER) and itsin vivometabolite fexofenadine (FEX) was performed. Both TER and FEX were subjected to high temperature at different pH and UV/VIS light at different pH and then quantitatively analyzed using new validated LC-UV methods. These methods were used to monitor the degradation processes and to determine the kinetics of degradation for both the compounds. As far as the effects of temperature and pH were concerned, FEX occurred more sensitive to degradation than TER. As far as the effects of UV/VIS light and pH were concerned, the both drugs were similarly sensitive to high doses of light. Using all stress conditions, the processes of degradation of TER and FEX followed the first-order kinetics. The results obtained for these two antihistaminic drugs could be helpful in developing their new derivatives with higher activity and stability at the same time.

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