See also Hormone Action Hormone Mechanisms of Action Hormone Hierarchy of Action Receptors with Protein Kinase Activity

Protein Kinase Cancer Therapies Picture

Thyroid Hormone Receptor Resource Figure 12.13 Signal transduction pathway involving adenylate cyclase. i Figure 12.13 Signal transduction pathway involving adenylate cyclase. i The insulin receptor (Figure 23. ) is a glycoprotein with an ot2. 2 tetrameric structure, stabilized by disulfide bonds. Both the ot chain (735 residues) and the fi chain (620 residues) are translated from a single mRNA, giving a polypeptide chain that then undergoes proteolytic processing. The ot chain, which is...

See also Action of Insulin from Chapter 23 Gluconeogenesis Control of Fatty Acid Synthesis Hormonal Regulation of Fuel

PEPCK is an enzyme of gluconeogenesis. It catalyzes conversion of the 4-carbon compound, oxaloacetate, to phosphoenolpyruvate (PEP), releasing CO2. The reaction requires energy input from GTP and produces GDP. Oxaloacetate + GTP < > PEP + CO2 + GDP For PEPCK to function in gluconeogenesis, oxaloacetate produced in the pyruvate carboxylase reaction in the mitochondria, must be transported to the cytoplasm. PEPCK is not under any known allosteric control. Activity of the enzyme is regulated...

AcetylCoA inhibits Pyruvate kinase and activates Pyruvate Carboxylase

Pyruvate Kinase Glucagon

Other control points on the two pathways are shown in Figure 16.6 The major allosteric regulatory factor of the two pathways is Fructose 2,6 bisphosphate. Note in Figure 16.7 that PFK-2 and Fructose 2,6-bisphosphatase are on the same peptide and are affected differently by phosphorylation see below . Interconversion of PFK-2 and Fructose 2,6-bisphosphatase depends on the level of cAMP which is stimulated by glucagon and epinephrine and is inhibited by insulin . Increasing cAMP glucagon...

See also Oxygen Binding by Heme Proteins Oxygen Binding by Myoglobin Oxygen Binding by Hemoglobin Hemoglobin Allostery

Structure His Myoglobinoxygen Bind

Figure 7.3 Comparison of myoglobin and hemoglobin. Li Figure 7.3 Comparison of myoglobin and hemoglobin. Li Figure 6.1 Three-dimensional folding of the protein myoglobin. Figure 6.1 Three-dimensional folding of the protein myoglobin. Myoglobin Hemoglobin Structure - The myoglobin-hemoglobin family of proteins employs Fe II for O2 binding. Throughout the myoglobin-hemoglobin family, the iron is chelated by a tetrapyrrole ring system called protoporphyrin IX, one of a large class of porphyrin...

Xanthosine Monophosphate

Amp Deaminase Uric Acid

Inosine Monophosphate IMP NAD H2O lt gt Xanthosine Monophosphate XMP NADH Subsequently, XMP is converted to GMP by the enzyme XMP aminase Figure 22.6 . See also De Novo Biosynthesis of Purine Nucleotides AMP Deaminase is an enzyme in purine catabolism that deaminates AMP to form IMP and ammonia, as follows See also Figure 22.7, Purine Degradation Figure 22.7 Catabolism of purine nucleotides to uric acid. Figure 22.7 Catabolism of purine nucleotides to uric acid. Figure 22.7 shows pathways of...

See also Glycogen Synthase Glycogen Biosynthesis Glycogen Synthase D cAMPDependent Protein Kinase Kinase Cascade

Glycogen Structure

Glycogen synthesis and breakdown are controlled tightly by hormonal action. These involve regulatory kinase cascades, as depicted in Figure 13.18 for glycogen breakdown. Like gluconeogenesis glycolysis, glycogen synthesis breakdown is reciprocally regulated. For example, epinephrine inhibits glycogen synthesis at the same time as it promotes glycogen breakdown. Glycogen synthase is the primary regulatory enzyme in glycogen synthesis. Like glycogen phosphorylase, the enzyme that breaks down...