Proteins Flashcards
What is a peptide?
The family of molecules formed from the linking in a define order, of various amino acids
What is the major compound that makes up proteins?
Nitrogen
What is the name of the bond that links to amino acids?
an amide bond or a peptide bond
What is a Polypeptide?
A group of amino acids bonded together from a few to 100 or more
What is an Oligopeptide?
A peptide of a small numbered chain of amino acid from 30-50 long
What is a depeptide?
A peptide of two amino acids in length with a hydrogen present
Where does amino acid absorption occur?
along the entire small intestine
How are amino acids transported across the brush boarder?
via Sodium dependent system
What influences the affinity of an amino acid to a carrier?
the hydrocarbon mass of its side chain and negative charge
Which are absorbed faster, branched chain aa, or smaller aa?
Branched chain
Which is absorbed fastest, neutral, basic or acidic aa?
neutral aa
Which are absorbed faster, essential or non-essential aa?
Essential
What aa are the slowest to be absorbed?
dicarboxylic (acidic) aa, such as Glutamate and aspartate
How are peptides transported?
via PEPT 1, which is associated with co-movement of protons
What type of transport is used to get amino acids across the basolateral border?
Sodium-independent transport, however sodium-dependent pathways are used when the concentration of aa in the gut are low
What are the main uses of amino acids?
1) Energy
2) Synthesis of; Apoproteins or lipoprotein formation, new digestive enzymes, hormones, and nitrogen-containing compounds
What is the enzyme that breaks down peptide within the enterocyte?
protease
break down of peptides, also called hydrolysis also occurs where else in the body?
in the plasma membrane in the liver, kidney, muscles or the cytosol of cells.
What carrier systems are used to transport amino acids into the liver?
1) Diffusion
2) Sodium dependent nitrogen system= Gluatmine, histidine
3) Hormones and cytokines such as interkluin-1 and TNF-alpha
4) System A induces glycagon and provides aa substrates for gluconeogenesis
5) System Gly is sodium dependent for glyceine
What carrier systems are used for the transport of aa into the kidneys?
1) Diffusion
2) y-glutamyl cycle (glutathione is the carrier)
What is the concentration of total protein in plasma?
7.5g/gL, which are mostly glycoproteins, simple proteins and lipoprotiens
What are the 5 plasma proteins and there functions?
1) Albumin- maintains oncotic pressure, and transports nutrients such as B6, zinc, calcium, copper, fatty acids, and drugs and hormones
2) Transthyretin- prelbumin
3) Retinol-binding protein- vitamin A and thyroid hormone transport.
4) Blood clotting proteins
5) Globulins
What are all the Globulins?
1) alpha 1 globulins- various glycoproteins and HDL’s
2) alpha 2 globulins- various glycoproteins, haptoglobin for free hemoglobin transport…
3) B- globulins- transferrin for ion and other mineral transport and LDL’s.
4) y- globulins- immunoglobulins or antibodies
What are the essential amino acids?
Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Typtophan Valine
What are the semi-essential amino acids?
Arginine
Histidine
Name four essential an four non-essential amino acids?
Essential: Isoleucine, leucine, lysine, Tryptophan
Non-essentia: Glutamine, Arganine, Serine, Glycine
What are the 5 Nitrogen containing non-protein compounds that are synthesised in the liver?
Glutathione Carnitine Creatine Carosine Choline
What aa make up Glutathione?
Cysteine, glycine, glutamate
What aa make up Carnitine?
Lysine, methionine
What aa make up creatine?
Arginine, glycine, methionine
What aa make up carnosine?
Histidine, B-alanine
What aa make up Choline?
Serine
