May 1, 1992

Alkaline p-nitrophenylphosphate phosphatase activity from Halobacterium halobium. Selective activation by manganese and effect of other divalent cations

The International Journal of Biochemistry
M L BonetE Cadenas


1. Alkaline p-nitrophenylphosphate phosphatase (pNPPase) activity of Halobacterium halobium is selectively stabilized and stimulated by Mn2+ ions. 2. Mn2+ binding to native pNPPase is characterized by a dissociation constant of 0.35 mM at pH 8.5, 37 degrees C, with a Hill coefficient of 0.988. 3. Mn2+ behaves as a mixed type nonessential activator, increasing the Vmax value (beta = 6.09, pH 8.5) and decreasing the Km value for pNPP (alpha = 0.56, pH 8.5). The Ki value for inorganic phosphate (a competitive inhibitor) was also decreased in the presence of Mn2+. 4. Activation of native pNPPase by preincubation with Mn2+ is a slow temperature-dependent process, which can be described by an exponential relationship vs time. However, a weak but immediate activation was also detected. 5. Zn2+, Cu2+ and Ni2+ were found to inhibit both native and Mn(2+)-stimulated pNPPase, whereas Co2+ and Cd2+ inhibited the Mn(2+)-stimulated pNPPase but had no effect on the native enzyme form.

  • References11
  • Citations9


  • References11
  • Citations9


Mentioned in this Paper

Cations, Divalent
Phosphoric Monoester Hydrolases
Phosphate Measurement
Phosphoric Monoester Hydrolase Activity
Inorganic Phosphate Measurement
Manganese Measurement
Enzyme Stability
Nitrophenyl Phosphatase

About this Paper

Trending Feeds


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.

Coronavirus Protein Structures

Deciphering and comparing the proteins of different coronaviruses forms a basis for understanding SARS-CoV-2 evolution and virus-receptor interactions. This feed follows studies analyzing the structures of coronavirus proteins, thereby revealing potential drug target sites.

DDX3X Syndrome

DDX3X syndrome is caused by a spontaneous mutation at conception that primarily affects girls due to its location on the X-chromosome. DDX3X syndrome has been linked to intellectual disabilities, seizures, autism, low muscle tone, brain abnormalities, and slower physical developments. Here is the latest research.

ALS: Stress Granules

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterized by cytoplasmic protein aggregates within motor neurons. TDP-43 is an ALS-linked protein that is known to regulate splicing and storage of specific mRNAs into stress granules, which have been implicated in formation of ALS protein aggregates. Here is the latest research.

Fusion Oncoproteins in Childhood Cancers

This feed explores the function of fusion oncoproteins in specific childhood cancers, including those from racial/ethnic minority and underserved groups, and to provide preclinical assessment of potential therapeutics and how fusion oncoproteins influence gene expression to perturb normal cellular programs to block lineage differentiation and development

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Regulation of Vocal-Motor Plasticity

Dopaminergic projections to the basal ganglia and nucleus accumbens shape the learning and plasticity of motivated behaviors across species including the regulation of vocal-motor plasticity and performance in songbirds. Discover the latest research on the regulation of vocal-motor plasticity here.

Mitotic-exit networks with cytokinesis

Cytokinesis is the highly regulated process that physically separates daughter and mother cells in late mitosis. The mitotic-exit network (MEN), the signalling pathway that drives mitotic exit, directly regulates cytokinesis. Discover the latest research on mitotic-exit networks with cytokinesis here.

DNA Replication Origin

DNA replication is initiated as specific gene sequences, called origins, that function to start DNA replication. Pre-replication complexes are assembled at these origins during the G1 phase of the cell cycle. These sequences allow for targeted activation or deactivation of replication. Discover the latest research on DNA replication origins here.