Proteins Lab Flashcards by SAM EMMANUEL FORMALEJO

Q

Identify the protein accdg to composition

yield only amino acids upon hydrolysis

A

simple proteins

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Q

Identify the protein accdg to composition

yield simple proteins and non-protein substances upon hydrolysis

A

conjugated proteins

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Q

Identify the protein accdg to solubility

soluble in water and dilute aqueous solutions

A

albumins (in plasma)

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Q

Identify the protein accdg to solubility

soluble in dilute salt solutions but are insoluble or sparingly soluble in water

A

globulins (in serum)

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Q

Identify the protein accdg to solubility

soluble in dilute solutions of acids and bases and insoluble in neutral solvents

A

glutelins

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Q

Identify the protein accdg to solubility

soluble in 50-90% of alcohol and insoluble in water, neutral solvents, or absolute alcohol

A

prolamins (stores protein in plants)

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Q

Identify the protein accdg to solubility

albumin-like that is insoluble in most ordinary solvents

A

albuminoids

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Q

what do you call the process resulting to a loss of 3D structure sufficient to render a protein functionless?

A

denaturation

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Q

two types of protein denaturation?

A

Irreversible denaturation
Reversible denaturation

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Q

two types of protein hydrolysis?

A

complete hydrolysis
incomplete/partial hydrolysis

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Q

Identify the protein hydrolysis type

uses a strong acid/base + high temperature and yields amino acids?

A

complete hydrolysis

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Q

Identify the protein hydrolysis type

uses enzymes called protease and yields a mixture of amino acids and oligopeptides

A

incomplete/partial hydrolysis

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Q

what is the most commonly used reagent for acid hydrolysis?

A

6M HCl

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Q

in acid hydrolysis, which of the amino acids are partially desctructed?

A

cys & tyr

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Q

in acid hydrolysis, which of the amino acids are completely destructed?

A

trp

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Q

in acid hydrolysis, which of the amino acids are incompletely liberated?

A

val & ile

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Q

in acid hydrolysis, which of the amino acids are racemized and destructed?

A

ser & thr

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Q

in acid hydrolysis, which of the amino acids are converted to acidic amino acids?

A

asn & gln

converted to asp & glu

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Q

what reagents are used in basic hydrolysis?

acid & base hydrolysis are under complete hehe

A

NaOH or KOH

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Q

in basic hydrolysis, which of the amino acids are not destroyed?

A

trp

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Q

in basic hydrolysis, which of the amino acids are destroyed?

A

arg, asn, gln, ser

RN QS

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Q

in partial hydrolysis, what do you need to facilitate the hydrolysis of peptide bonds?

A

catalysts

which are enzymes

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Q

what do you call the type of hydrolysis that requires the presence of proteolytic enzymes that results to either partial or selective hydrolysis of polypeptide to yield a mixture of peptide fragments?

A

enzymatic hydrolysis

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Q

what do you call the enzymes that hydrolyze peptide bonds at specific sites?

A

proteases

or peptidases

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What are the 3 exopeptidases?

- Carboxypeptidase A - Carboxypeptidase B - Aminopeptidase

3 Endopeptidases?

- Trypsin - Chymotrypsin - Papain

What exopeptidase cleaves C-terminal residues except R, K, and P? ## Footnote cleaves or catalyzes hydrolysis

Carboxypeptidase A

What exopeptidase cleave C-terminal residues of R or K? ## Footnote cleaves or catalyzes hydrolysis

Carboxypeptidase B

what exopeptidase cleaves most N-terminal ends except when P is the next residue? ## Footnote cleaves or catalyzes hydrolysis

Aminopeptidase

what endopeptidase cleaves at the C-side of R & K? ## Footnote cleaves or catalyzes hydrolysis

Trypsin

What endopeptidase cleaves at the C-side of F, Y, and W? ## Footnote cleaves or catalyzes hydrolysis

Chymotrypsin

What endopeptidase cleaves the C-side of hydrophobic groups or aromatic R-groups? ## Footnote cleaves or catalyzes hydrolysis

Papain

What do you call the procedure in which the pH of a protein mixtreure is adjusted to the pI of the protein to be isolated to selectively minimize its solubility?

Isoelectric precipitation

Proteins are soluble at ____ salt concentration | high or low

low

What do you call the process wherein you add low concentrations of salt to a protein solution? ## Footnote this increases the solubility of proteins and is related to the nonspecific effect the salt has on the ionic strength.

salting in ## Footnote Salt molecules stabilize protein molecules by decreasing the electrostatic energy between the protein molecules which increase the solubility of proteins

What do you call the process wherein the ionic strength of a protein solution is increased by adding more salt (high salt conc.) and results to a decreased solubility and thus protein precipitation?

Salting out ## Footnote the salt molecules compete with the protein molecules in binding with water

2 protein components of cow's milk?

- Casein - Whey proteins

Ano yung protein from milk isolated by Isoelectric precipitation and is present as micelles in it? | also acts as storage for amino acids in milk

casein

Anong protein from skimmed milk ang ma-iisolate via denaturation and coagulation by heat? | also the second major protein in milk; regulatory protein in lactose

Albumin

what protein can be seen in beef muscle and is isolated through salt-induced precipitation?

myoglobin

This is the protein present in muscles that stores oxygen and is a hemoprotein

myoglobin

what protein is isolated from wheat flour via solubility difference?

gluten

what do you call the protein that is considered as a composite of prolamin and glutelin, which exist, conjoined with starch?

Gluten

What protein is a storage protein responsible for the elasticity and extensibility of the dough?

Gluten

Gluten traps ____ produced by the reaction of flour and yeat and gives flour its characteristic chewiness

CO₂

The principle in the isolation of gluten from wheat flour is its difference in solubility wherein starch is ____ in H₂O while gluten is ____ in H₂O. | soluble or ins or partially sol

partially soluble; insoluble

What solution is used to test the complete removal of starch?

Iodine (I₂) solution ## Footnote product is yellowish-white solid, tough, elastic, and sticky

# Identify the qualitative reactions test Used to detect the presence of peptide bonds

Biuret test

positive test for biuret test

pink to violet to blue coloration

# Identify the qualitative reactions test detects free alpha-amino acids and amines

Ninhydrin test

positive test of ninhydrin test?

blue to blue-purple color or yellow-orange product (if proline)

# Identify the qualitative reactions test detects aromatic amino acids

Xanthoproteic test ## Footnote (F, W, Y)

positive result of Xanthoproteic test?

yellow sol'n (orange if xcess naoh)

# Identify the qualitative reactions test detects phenolic group in tyrosine

Millon's test

positive test for Millon's test?

old rose/flesh/purple-red ppt

# Identify the qualitative reactions test detects indole group in trp

Hopkins-Cole test

positive result of Hopkins-Cole test

pink to violet interface

# Identify the qualitative reactions test detects guanidino group of arg

Sakaguchi test

positive result of Sakaguchi test?

red to red-orange color

# Identify the qualitative reactions test detects sulfur-containing amino acids | M & C

Fohl's or Lead Acetate test

positive result of Fohl's/Lead acetate test

brown or black ppt

# Identify the qualitative reactions test detects the presense of his and tyr

Pauly's test/Diazo rxn

positive result of Pauly's test/Diazo rxn

red color

# Identify the qualitative reactions test detects the presence of -SH group (cys)

Nitroprusside test

positive result of nitroprusside test

red coloration

# Identify the qualitative reactions test detects the presence of prim, 2ndary, and tert amides and nitriles

Amide test

positive result of Amide test

red litmus to blue litmus paper ## Footnote kasi nga basic ang amides

# Identify the qualitative reactions test based on principle Complexation of Cu²⁺ with a peptide bond

Biuret test

# Identify the qualitative reactions test based on principle oxidative decarboxylation and deamination followed by condensation

Ninhydrin test

# Identify the qualitative reactions test based on principle nitration of aromatic ring

Xanthoproteic test

# Identify the qualitative reactions test based on principle complexation (mercuration and nitration of nitrohydroxyphenyl derivatives with Hg²⁺)

Millon's test

# Identify the qualitative reactions test based on principle reduction of oxalate to glyoxylate then the condensation of two trps with glyoxylic acid

Hopkins-Cole test

# Identify the qualitative reactions test based on principle base-catalyzed condensation of alpha-naphthol with the guanidino group of arg

Sakaguchi test

# Identify the qualitative reactions test based on principle degradation and substitution reaction to form PbS

Fohl's/Lead Acetate test

# Identify the qualitative reactions test based on principle diazotized sufanilic acid couple with amino phenol to form a color red azo compound in cold condition

Pauly's test/Diazo rxn

# Identify the qualitative reactions test based on principle complexation via the addition of Na₂Fe(CN)₅NO in dilute NH₃

Nitroprusside test

# Identify the qualitative reactions test based on principle base-catalyzed hydrolysis

Amide test

what do you call the test used to separate and identify components or solutes in a mixture and is based on affinity principle?

Chromatography

What is the stationary phase composed of in our exp?

Silica gel

The mobile phase in TLC is comprised of?

ButOH:HOAc:H₂O (4:1:5) | Butanol:Acetic acid:Water ## Footnote butanol is tert-butyl alcohol pero butanol n lng para madali hehe (or tert-butanol idk if pwede)

TLC is visualized using what?

ninhydrin

RF (Retention factor) is computed by?

distance of amino acid/distance of solvent

Stages in TLC?

1. Sample/Std. Application 2. Development 3. Visualization 4. Evaluation 5. Documentation

a simple colorimetric and one of the most commonly used assay for total protein concentration. It is based on the proportional binding of **Coomassie dye to proteins**

Bradford Assay

how much protein should u use in Bradford assay (in mg)?

10-100 mg

what is the standard used in Bradford assay?

bovine serum albumin | BSA

the bradford reagent is acquired by dissolving the dye in ____ and ____

ethanol and phosphoric acid