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‫תכונותיהן של החומצות האמיניות‬
‫חומצות אמיניות הידרופוביות‬
‫‪A, Ala, alanine‬‬
‫עתה סומן חלקה של חומצת האמינו שמשותף‬
‫לכל הסוגים‬
‫אלנין‬
‫מתיונין‬
‫ואלין‬
‫לאוצין‬
‫פנילאלנין איזולאוצין‬
‫פרולין‬
‫‪Alanine‬‬
‫‪Valine‬‬
‫‪Phenylalanine‬‬
‫‪Proline‬‬
‫‪Methionine‬‬
‫‪Leucine‬‬
‫‪Isoleucine‬‬
‫יחודו של האלנין הוא הקבוצה המתילית שמקנה‬
‫למולקולה אופי הידרופובי‬
‫לבסוף‪ ,‬אינכם צריכים לזכור את הפרטים לגבי כל חומצת‬
‫אמינו אלא לדעת על סמך נוסחאות המבנה‪ ,‬שינתנו לכם‪,‬‬
‫מהן התכונות של כל אחת מחומצות האמינו‪.‬‬
‫תכונותיהן של החומצות האמיניות‬
‫חומצות אמיניות הידרופוביות‬
V, Val, valine
Alanine
Valine
Phenylalanine
Proline
Methionine
Leucine
Isoleucine
Valine has two methyl groups
it's somewhat
larger, rather more hydrophobic.
Soso
here
we have valine.
‫תכונותיהן של החומצות האמיניות‬
F, Phe, phenylalanine
‫חומצות אמיניות הידרופוביות‬
Alanine
Valine
Phenylalanine
Proline
Methionine
Leucine
Isoleucine
This has this benzene ring,
Andthis
weunsubstituted
have phenylalanine.
benzene ring, very hydrophobic
‫תכונותיהן של החומצות האמיניות‬
‫חומצות אמיניות הידרופוביות‬
P, Pro, proline
Alanine
Valine
Phenylalanine
Proline
Methionine
Leucine
Isoleucine
Here's proline. Proline is a little different because it folds back onto the main chain of the
So proline has all of these CH2's, so it's very hydrophobic and it links back to the
amino acid. So, strictly
speaking,
an imino
acid
instead
nitrogen
of theproline
amino isgroup
of the
amino
acid.of an amino acid but
most biochemists don't make that distinction.
‫תכונותיהן של החומצות האמיניות‬
M, Met, methionine
‫חומצות אמיניות הידרופוביות‬
Alanine
Valine
Phenylalanine
Proline
Methionine
Leucine
Isoleucine
methionine has a sulfur in here. It's one of two amino acids
Methionine,
with a sulfur, and again it's very hydrophobic
‫תכונותיהן של החומצות האמיניות‬
‫חומצות אמיניות הידרופוביות‬
Alanine
Valine
Phenylalanine
Proline
Methionine
Leucine
Isoleucine
L, Leu, leucine
leucine,
lot's of CH's,
CH3's.
AndHere's
then we
have leucine
and isoleucine.
‫תכונותיהן של החומצות האמיניות‬
‫חומצות אמיניות הידרופוביות‬
I, Ile, isoleucine
Alanine
Valine
Phenylalanine
Proline
Methionine
Leucine
Isoleucine
lots of CH2's and CH
Isoleucine
is almost
are the
thehydrophobic
same,
amino acids.
3's. So those
‫תכונותיהן של החומצות האמיניות‬
‫חומצות אמיניות טעונות‬
Aspartic acid (aspartate)
Glutamic acid (glutamate)
Lysine
Arginine
Histidine
D, Asp, aspartate
aspartate,
glutamate,
charged
Then we
amino
lysine,
arginine,
the an example
histidine.of an acidic group.
So
aspartate
ishave
the
simplest,
it just has a CH2 and
a carboxyl
group,
and
so acids;
that's
‫תכונותיהן של החומצות האמיניות‬
E, Glu, glutamate
‫חומצות אמיניות טעונות‬
Aspartic acid (aspartate)
Glutamic acid (glutamate)
Lysine,
Arginine,
Histidine
are the
two same
CH2'sthing,
and abut
carboxyl
GlutamateSee
has there
basically
with angroup
extra CH2 in it.
‫‪Chinese restaurant syndrome‬‬
‫תסמונת המסעדה הסינית‬
‫‪MSG (monosodium glutamate) is abused as a‬‬
‫‪flavor enhancer in some restaurants, including‬‬
‫‪some Chinese restaurants. People who are‬‬
‫‪sensitive to MSG get a sensation like a clamp‬‬
‫‪placed over their head and tightened. Fortunately,‬‬
‫‪the sensation is temporary.‬‬
‫( ‪MSG‬מונוסודיום גלוטמט) משמש להוספת טעם במסעדות‬
‫מסוימות‪ .‬בעיקר הוא נפוץ במסעדות סיניות‪ .‬ישנם אנשים‬
‫הרגישים לחומר זה ובעת האכילה נתקפים ברגישות‬
‫המתבטאת בלחץ גדול בראשם שהולך וגדל‪ .‬למזלם כאב‬
‫הראש הוא זמני‪.‬‬
‫זהו מלח נתרני של החומצה האמינית ח ‪.‬גלוטמית ‪,‬מונומר‬
‫הנמצא כמרכיב כמעט בכל החלבונים‪.‬‬
‫תכונותיהן של החומצות האמיניות‬
K, Lys, lysine
Charged amino acids
Aspartic acid (aspartate)
Glutamic acid (glutamate)
Lysine,
Arginine,
Histidine
this has a nitrogen forming
this amino group
This
atisthe
lysine
end the
which
basic
is
the
one,
basic group and
this
hydrocarbon
chain
‫תכונותיהן של החומצות האמיניות‬
Charged amino acids
R, Arg, arginine
Aspartic acid (aspartate)
Glutamic acid (glutamate)
Lysine,
Arginine,
Histidine
Arginine has these three nitrogens and here we can have a charge on this
guanidino group Here's
up here,
so that's another basic residue.
arginine.
‫תכונותיהן של החומצות האמיניות‬
Charged amino acids
H, His, histidine
Aspartic acid (aspartate)
Glutamic acid (glutamate)
Lysine,
Arginine,
Histidine
Andnitrogen
then we here
havecan
histidine.
Histidine
is very interesting
its pK
very close to
this
be positive
or negative
dependingbecause
on a variety
of is
circumstances.
thea pH
in theyou
body,
and
soat
the
charge
onof enzymes.
And so this is
residue
often
find
active
sites
‫תכונותיהן של החומצות האמיניות‬
Polar amino acids
Serine
Threonine
Tyrosine
Cysteine
Asparagine
Glutamine
Tryptophan
S, ser, serine
Polar means that they interact well with water, so it's the opposite of hydrophobic. So
these are
ones threonine,
which
have
groups
on
which
will
hydrogen
bonds and interact
serine,
Let's
tyrosine,
move
cysteine,
onto
the
polar
asparagine,
amino
acids.
glutamine,
tryptophan.
Serine
has
a hydroxyl
group.
It's very
simple
just
athem
methyleneand
aform
hydroxyl
group
well with water. So this is the list:
‫תכונותיהן של החומצות האמיניות‬
Polar amino acids
T, Thr, threonine
Serine
Threonine
Tyrosine
Cysteine
Asparagine
Glutamine
Tryptophan
methyl
group in addition.
Then threonine
has a
‫תכונותיהן של החומצות האמיניות‬
Polar amino acids
Serine
Threonine
Tyrosine
Cysteine
Asparagine
Glutamine
Tryptophan
Y, Tyr, tyrosine
Tyrosine is a little more complex,
ithydroxyl
has the benzene
group outring
here
but
making
it only ithas
polar.
this
‫תכונותיהן של החומצות האמיניות‬
Polar amino acids
Serine
Threonine
Tyrosine
Cysteine
Asparagine
Glutamine
Tryptophan
C, Cys, cysteine
Cysteine is the other amino acid with a sulfur in it, and you
And if we move onto cysteine.
can see it again is very simple with that sulfur present.
‫תכונותיהן של החומצות האמיניות‬
Polar amino acids
Serine
Threonine
Tyrosine
Cysteine
Asparagine
Glutamine
Tryptophan
N, Asn, asparagine
this carbonyl and amine group here. This group does not ionize, so it is not
And
we have
asparagine.
again
has
a single
CH
group and
now
it has
charged. It isThis
not acidic;
it'sthen
not
basic.
It 2doesn't
ionize
in the
body. It's polar
because it interacts well with water, but it's not ionized.
‫תכונותיהן של החומצות האמיניות‬
Polar amino acids
Serine
Threonine
Tyrosine
Cysteine
Asparagine
Glutamine
Tryptophan
Q, Glu, glutamine
thisan
polar
group
at
the
end. and again it has
Glutamine justSame
has
thing
additional
goes for
CHglutamine.
2 group
‫תכונותיהן של החומצות האמיניות‬
Polar amino acids
Serine
Threonine
Tyrosine
Cysteine
Asparagine
Glutamine
Tryptophan
W, Trp, tryptophan
these
fused
here
actually
is can
the form
dominant
feature.
So acids,
although
tryptophan
is
often
People
It has
usually
this rings
nitrogen
put
tryptophan
here
whichin
grouphydrogen
of polar
amino
bonds
which but
gives
personally
it some polar
I don't
So
finally,
the
last
one
on
here
is
tryptophan.
put in this group,
it really has
ainmixture,
some
of
the nature
others of
do, of properties.
character,
butreally
practice
agreeas
the
with
nonthat.
polar
‫תכונותיהן של החומצות האמיניות‬
Glycine
G, Gly, glycine
is just a hydrogen atom. So this is basically just a very quick run-through of the amino
acids, and as we talk about them more and see how they're used, you'll get more
familiar with them and
how
they
work
and
see
howuntil
theirlast,
different properties are
the see
simplest
And
one
then
of
all,
there's
which
glycine,
I kept
important. Today what I really wanted to get across was the nature of the forces between
amino acids and the properties of the amino acids, which are important.