Jun 1, 1993

pH studies to elucidate the chemical mechanism of penicillin acylase from Kluyvera citrophila

Biotechnology and Applied Biochemistry
J MartínR Arche

Abstract

The variation with pH of the kinetic parameters of penicillin acylase from Kluyvera citrophila has been used to gain information about the chemical mechanism of the reaction catalysed by the enzyme. The pH-dependence of log (V/Km) for penicillin G showed that a group with a pK value over 4.7 must be deprotonated and that a group with a pK value over 9.7 must be protonated in the free enzyme for activity. The solvent perturbation and temperature studies indicated that these groups are respectively of cationic and neutral acid type with ionization enthalpies of 29.7 and 111 kJ/mol. It was proved that penicillin G sulphoxide is a reversible linear competitive inhibitor with respect to the hydrolysis of penicillin G. The similarity of the pH profile and the magnitude of the pK values derived from the dissociation constant, Ki, suggest that both groups are concerned with the binding of penicillin G and its analogues to the enzyme. It is proposed that binding of substrate involves the formation of hydrogen bonds between the substrate and the essential ionizable groups in the enzyme which lie within the hydrophobic environment of the active site of penicillin acylase. This suggestion is supported by the finding that the profile of V (...Continue Reading

  • References
  • Citations

References

  • We're still populating references for this paper, please check back later.
  • References
  • Citations

Citations

  • This paper may not have been cited yet.

Mentioned in this Paper

Catalysis
Ursopen
Penicillin G sulfoxide, monosodium salt
ACY1
Van-Pen-G
Hydrogen-Ion Concentration
Penicillin V Acylase
Paracolobactrum

About this Paper

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

Head And Neck Squamous Cell Carcinoma

Squamous cell carcinomas account for >90% of all tumors in the head and neck region. Head and neck squamous cell carcinoma incidence has increased dramatically recently with little improvement in patient outcomes. Here is the latest research on this aggressive malignancy.

Signaling in Adult Neurogenesis

Neural stem cells play a critical role in the production of neuronal cells in neurogenesis is of great importance. Of interest is the role signalling mechanisms in adult neurogenesis. Discover the latest research on signalling in adult neurogenesis.

Psychiatric Chronotherapy

Psychiatric Chronotherapy considers the circadian rhythm as a major factor for optimizing therapeutic efficacy of psychiatric interventions. Discover the latest research on Psychiatric Chronotherapy here.

Bone Marrow Neoplasms

Bone Marrow Neoplasms are cancers that occur in the bone marrow. Discover the latest research on Bone Marrow Neoplasms here.

IGA Glomerulonephritis

IgA glomerulonephritis is a chronic form of glomerulonephritis characterized by deposits of predominantly Iimmunoglobin A in the mesangial area. Discover the latest research on IgA glomerulonephritis here.

Cryogenic Electron Microscopy

Cryogenic electron microscopy (Cryo-EM) allows the determination of biological macromolecules and their assemblies at a near-atomic resolution. Here is the latest research.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.