Lecture 12 and 13; Proteins

What are the components of amino acid structure

amine group, carboxyl, C, H, and R group

What are the elements always present in AA

C, H, O, and N

How do we classify AA

by their R groups

How are peptides formed

AA form peptide bonds

Primary structure of AA

AA sequence

Secondary structure of AA

alpha helix and beta pleated sheets

Tertiary structure of AA

3D R group interactions

Quaternary structure of AA

more than one peptide

2 steps of Protein digestion

begins in stomach and then by pancreatic and SI enzymes

Where are AA and small peptides absorbed

small intestine protein transporters

3 general functions of AA

make proteins, make small molecules, use for energy

Central Dogma

DNA->RNA->Protein

Transcription

DNA->RNA

Translation

RNA->Protein

Protein functions

structural, blood proteins, enzymes, hormones, biosignalling, immune function, complexed with other nutrients

Urea cycle

NH3->urea

Why do animals go through the urea cycle

to make nitrogen safe to travel in blood

Nitrogen recycling

urea from urea cycle travel back to the RRO through saliva or back across the epithelium

Why do ruminants go through nitrogen recycling

microbes can build AA with urea and a c-skeleton

How do we classify protein

animal vs. plant, ruminant vs. nonruminant, AA profile, protein digestibility

Is plant or animal AA profile more favorable for animals

animal

Is plant or animal AA profile more digestible for animals

plant

Low RDP and high RUP

animal protein

High RDP and low RUP

plant protein

Two non-protein nitrogen sources

urea and single AA

Where do AA come from for non-ruminants

feed and endogenous cells

Endogenous cells

dead cells within animals that are digested in the GIT

What are the source of AA for ruminants

feed, endogenous, and rumen microbes

First limiting AA

first AA to become deficient in the diet and limits animal protein synthesis

What AAs can be first limiting AA

10 essential FA