The cytosolic isozymes has two distinct function, It catalyzes the conversion of citrate to isocitrate, providing the substrate for a cytosolic isocitrate dehydrogenase that generates NADPH as reducing power for fatty acid synthesis and other anabolic processes in the cytosol. It also has a role in cellular iron homeostasis

#Id: 8754

#Unit 1. Structure and Function of Biomolecules

#Id: 8755

#Unit 1. Structure and Function of Biomolecules

Thermodynamic measurements indicate that native proteins are only marginally stable under physiological conditions. The free energy required to denature them is ∼0.4 kJ ∙ mol−1 per amino acid residue.

#Id: 8756

#Unit 1. Structure and Function of Biomolecules

#Id: 8757

#Unit 1. Structure and Function of Biomolecules

A fully folded 100-residue protein is only about 40 kJ ∙ mol−1 more stable than its unfolded form (for comparison, the energy required to break a typical hydrogen bond is ∼20 kJ ∙ mol−1).

#Id: 8758

#Unit 1. Structure and Function of Biomolecules

The combined hydrophobic and hydrophilic tendencies of individual amino acid residues in proteins can be expressed as hydropathies. The greater a side chain’s hydropathy, the more likely it is to occupy the interior of a protein.

#Id: 8759

#Unit 1. Structure and Function of Biomolecules

Hydrogen bonds, which are central features of protein structures, make only minor contributions to protein stability.