TLS Online TPP Program

#Id: 9292

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 9293

#Unit 6. System Physiology – Plant

Ammonium assimilation in roots

TLS Online TPP Program

#Id: 9294

#Unit 6. System Physiology – Plant

Nitrate reductase

Homodimers, two identical subunits

Each subunit with 100kD

Each subunit contains 3 prosthetic groups:

FAD, heme, and molybdenum complexed to pterin (an organic molecule). 

TLS Online TPP Program

#Id: 9295

#Unit 6. System Physiology – Plant

The nitrate reductase dimer- Three binding domains

TLS Online TPP Program

#Id: 9296

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 9297

#Unit 6. System Physiology – Plant

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.