AA for nonprotein N compounds

• Protein turnover: need to replace old proteins, varies based on conditions, tissues, between MPS and MPB
• Protein synthesis and degradation is a regulated process: transcription, translation, additional processing, protein degradation
• MTORC1: protein kinase, key regulator of protein synthesis/degradation, insulin regulates mTORC1 with same pathway that initiates GLUT4 translocation\
• Insulin activates P13-Akt, which activates mTORC1
• active mTORC1 phosphorylates downstream substrates to upregulate protein synthesis and suppress autophagy
• cancer tissue: want to turn mTORC1 off because it produces more cancerous proteins if on
• combo of insulin, leucine activates mTORC1
• AA metabolism gives C into pathways to fuel metabolism
• AA classification: glucogenic, ketogenic (making acetyl CoA), both
• Lysine and Leucine: strictly ketogenic, cannot be used to generate glucose
• Odd numbered FA: glucogenic because they can make succinyl-CoA: goes into oxaloacetate: pyruvate
• Acetyl CoA cannot be used to synthesize glucose: 2 Cs of it are lost to CO2 in earlier steps of pathway
• Odd Numbered FA: dairy products, C is conserved bc enters pathway via succinyl-CoA
• Urea synthesis: NH4 in liver mito (carbamoyl phosphate synthase) = carbamoyl phosphate, which takes N out of mito. Alanine deamination supplied the N group
• Urea synthesis: aspartate combines its N group with carbamoyl phosphate N group. Combines them with fumarate (C skeleton) to make arginine. Arginine into urea.
• high catabolic state = high urea output