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Proteins
Pavel Vrtílek
• High molecular matters, proteins of
human body are compounded around
from twenty amino acids.
• AMK are form a part all organism cells
and they must be forever innovated.
• Production of own proteins is dependent
on their entry from food products.
• Proteins are single source of nitrogen and
sulphur, which are not included in other
nutrients.
Division proteins
1. Simple – include only protein constituent
• histones
• albumins
• globulins
• fibrilar proteins (skleroproteins - colagen,
elastin)
• plant proteins (prolamins, gluteins)
2. Compound – except protein include also other
non-proteins constituent (e. g.: suggars, nukleo
(nukleové) acids or lipids)
• glykoproteins – with suggar constituent
• lipoproteins – with lipid constituent
• chromoproteins – with contents dyes
• metaloproteins – in your molecule contained metal
(e. g. Fe, Zn, Se)
• fosfoproteins– with molecule of phosphorus acid
• nukleoproteins – with chains of nucleic acids
Fyziological function proteins
• structural and protective (colagen in bones and
connective tissues; elastins in tendons and skin;
ceratins in hair and nails; fosfolipoproteins as
contituent of cellular membranes)
• transport and storage(skladovací) (transferin
transfering Fe, feritin as reserve Fe, albumins
as porters of mineral matters, lipoproteins and
fosfolipoproteins transfering lipids)
• mechanical-chemical (actin and myozin as
proteins muscles; structural proteins
bones; clotting proteins podílející se
srážení)
• control (řídící) and regulative
• defensive and protective (obranné a
ochranné)
Structure
• Principal of structural stone of proteins are
amino acids, which are bonded by peptide
bonds.
• In higher organisms are always in L-form
(bacterie, antibiotica and in D-form), where
amino group (NH2) single AMK (se váže)
with karboxylic group (COOH) double AMK.
H O
H O
NH2 - C - C - OH - HNH - C - C - OH
R1
R2
• For reaction two molecules AMK split (se
odštěpí) molecule water = peptid.
Glutathion-S-transferasa (GST EC 2.5.1.18) = dimer protein
Procentual representation single amino acids in molecule
GST (100 % = 222 AMK)
Izoforms GST in human body
1) a-GST in hepatocyts
2) p-GST in epitel gall passages ( žlučových
cest)
Izoforms GST in kidneys
1) a-GST in proximal tubuls
2) p-GST in distal tubuls
According to number (Podle
počtu) AMK distinguish:
• dipeptides ( 2 AMK)
• tripeptides, tetrapeptides
• oligopeptides (5-10 AMK)
• polypeptides (11-100 AMK)
• proteins - macropeptides (over 100 AMK)
Amino acids distinguish on:
• essential (necessary), which must
organism entry in food,
• semiessential, which are necessary; in
specific situations (growth) and
• non-essential, which organism needs, but
can form.
(které organizmus sice potřebuje, ale
dokáže si je vytvořit).
Essential AMK:
• leucin, izoleucin, valin
• methionin, fenylalanin, lyzin
• threonin, tryptofan
Semiessential AMK:
• histidin, arginin (period of growth) - for
children
• tyrosin (colaps kidneys)
Non-esencial AK:
• glycin, (glutamová) acid, glutamin
• serin, taurin, alanine, ornitin, tyrozin
• cystein, prolin, hydroxyprolin
• (asparagová) acid, asparagin
• carnitin - 98% from total contents this
matter in organism is in muscles