Nitrite reductase

Nitrite (NO2-) is a highly reactive, potentially toxic ion.

Plant cells immediately transport the nitrite into chloroplasts or plastids.

The enzyme nitrite reductase reduces nitrite to ammonium.

Leaf chloroplasts and root plastids contain different forms of nitrite reductase.

Each polypeptide contains two prosthetic groups, an iron-sulfur group and a specialized heme.

NO3-, high sucrose conc, and light induce the transcription of nitrite reductase mRNA.

Asparagine and glutamine repress the induction.

TLS Online TPP Program

#Id: 9297

#XL - Q Biochemistry

Nitrite reductase

Nitrite (NO2-) is a highly reactive, potentially toxic ion.

Plant cells immediately transport the nitrite into chloroplasts or plastids.

The enzyme nitrite reductase reduces nitrite to ammonium.

Leaf chloroplasts and root plastids contain different forms of nitrite reductase.

Each polypeptide contains two prosthetic groups, an iron-sulfur group and a specialized heme.

NO3-, high sucrose conc, and light induce the transcription of nitrite reductase mRNA.

Asparagine and glutamine repress the induction.

TLS Online TPP Program

#Id: 9297

#XL - S Microbiology

Nitrite reductase

Nitrite (NO2-) is a highly reactive, potentially toxic ion.

Plant cells immediately transport the nitrite into chloroplasts or plastids.

The enzyme nitrite reductase reduces nitrite to ammonium.

Leaf chloroplasts and root plastids contain different forms of nitrite reductase.

Each polypeptide contains two prosthetic groups, an iron-sulfur group and a specialized heme.

NO3-, high sucrose conc, and light induce the transcription of nitrite reductase mRNA.

Asparagine and glutamine repress the induction.

TLS Online TPP Program

#Id: 8763

#XL - T Zoology

Thermophilic proteins have increased amounts of Arg, increased occurrence of Ala in helices, and Gly/Ala substitutions (which affect the entropy of the denatured state, and thus its free energy) and increased number of salt bridges. 

TLS Online TPP Program

#Id: 8764

#XL - T Zoology

Some thermostable proteins are stabilized by an increased size of the protein’s hydrophobic core, an increased size of the interface between its domains and/or subunits, and a more tightly packed core as evidenced by a reduced surface-to-volume ratio.

TLS Online TPP Program

#Id: 8765

#XL - T Zoology

Disulfide bonds are believed to increase the stability of the native state by decreasing the conformational entropy of the unfolded state due to the conformational constraints imposed by cross-linking (i. e. decreasing the free energy of the unfolded state).  

TLS Online TPP Program

#Id: 8766

#XL - T Zoology

Most protein have "loops" introduced by disulfides of about 15 residues

TLS Online TPP Program

#Id: 8767

#XL - T Zoology

Guanidinium ion and urea are chaotropic agents which disrupts hydrophobic core of proteins.

TLS Online TPP Program

#Id: 8768

#XL - T Zoology