Proteins - Summary II Flashcards
The a-chains of collagen are (left/right)-handed helixes
left
__________ are used in combination with papain in beer chill-proofing
Bacterial proteases
_______ form the lipovitellin fraction
HDLP
_______ hydrolyses a-1-4 glycosidic bonds within starch
amylase
_______ is used as a ________ on inferior meat cuts
Papain meat tenderizer
________ are water soluble and correspond to blood serum proteins of the chicken.
Livetins
_______ are activated as the Ca2+ concentration in the ________ increases postmortem.
Calpains sarcoplasm
The purpose of the process of surimi is to remove strong _______ compounds and pigments as well as ________ proteins that can interfere with the gelation of the myofibrillar proteins
flavor water-soluble
________ consists of two polypeptide chains of identical sequence termed a1, and another chain termed a2, and is the dominant type in meat
Type 1 collagen
______ can be inhibited by vitamin C, bi-sulfites, and EDTA
Polyphenol oxidase
Hydrolysis by ________ results in dextrins, maltose, and maltotriose
a-amylase
_________ arise from crosslinking between allysine, which is formed by _____ of lysine residue by lysyl oxidase, and an adjacent unmodified lysine residue
Lysinorlysine oxidation
What causes dark, firm, and dry (DFD) meat?
- Lack of glycogen - Early termination of glycolysis - High pH (> 6.0)
__________ sequesters the iron and prevents a red discoloration of the meringue due to conalbumin-iron complex.
Citric acid
_______ is employed in biomedical research by taking advantage of its high affinity for biotin in immunoassays, affinity chromatography, and molecular labelling
Avidin
From a functional standpoint, ______ proteins such as ______ are known to have good gelling ability.
globular ovalbumin
The carbohydrate in ________ is present as three polysaccharide chains, each attached to the polypeptide through an asparaginyl residue.
ovomucoid
Soybean is exceptionally rich in _______ and can serve as a valuable supplement to cereal foods
lysine
Fish myoglobin contains a _____ residue that is absent in mammalian myoglobin. Myoglobin and other pigments are concentrated in the _____ muscle.
cysteine dark
Soy protein isolates (SPI)
Wheat, corn, barley, rice
_______ is the only egg-white protein to contain a free sulfhydryl group
Ovalbumin
________ converts colloidal pectin to non-colloidal pectin
Pectin methyl esterase
_________ consists of three identical chains of a1
Type III collagen
__________________performs more favourably than acetic or citric acid at pH 6.0, but __________ is important in that it sequesters the iron and prevents a red discoloration of the meringue due to conalbumin-iron complex.
Potassium acid tartrate citric acid
Hydrolysis by ________ results in maltose
B-amylase
______ is soluble in weak salt solutions and to some extent in water
Phosvitin
The solubility of soybean proteins in water is (affected/unaffected) by the pH
strongly affected
The delay phase ends when ______ becomes depleted, because _________ alone cannot produce ATP fast enough to match the rate at which it is being hydrolyzed in the cell
CrP anaerobic glycolysis
______ are bland in flavor, light in color, and have a number of functional properties such as gelation,viscosity,emulsification,water holding capacity,and even some foaming and whipping ability.
Soy protein isolates (SPI)
__S is glycinin, the principal protein of soybeans with a built of 12 subunits
11
Depletion of ATP results in an inability to dissociate ____ from ____ and hence the muscle cannot relax, which is the onset of _____
myosin actin rigor mortis
In soybean, the limiting amino acids are the ones containing ______, which are ______ and _______
sulfur methionine cystine
Fe(III) is _____, Fe(II) bound to O2 is _____, Fe(II) bound to water is ______
metmyoglobin oxymyoglobin deoxymyoglobin
Does the first or second phase of heating release more fluid?
The second
________ enzymes are found in papaya
Papain
__S fraction is composed of a-conglycinin and low molecular weight polypeptides
2
The innermost part of the endomysium consists primarily of _____ collagen, which forms a sheet-like _________
Type IV non-fibrous network (group 2)
The principal component of __S is B-conglycinin, a sugar containing globulin
7
If isolated and hydrated, _____ will form a very viscous solution
gliadin
The major globular protein in albumen is _______
ovalbumin
The portion of the soybean that contains mostly carbohydrates is the _____
hull
__________ causes loss of cloud in citrus juice
Pectin methyl esterase
___________ are important to “dextrinize” the disrupted starch granules in baking
a-amylases
Which pH would result in the formation of a transparent gel?
7.0 > pH > pI
With _______ electrostatic repulsion at _____ ionic strength or at 7.0 > pH > pI, three dimensional networks form a transparent gel.
decreasing low
________ is a multi-type serine protease inhibitor with a molecular weight of 50 kDa, and comprises seven domains conferring trypsin,chymotrypsin,and elastase inhibitory activity.
Ovoinhibitor
_______ exhibits enzymatic activity over a broad range of temperatures, and can withstand boiling water for 1-2 minutes
Lysozyme
In collagen, hydrogen bonding occurs between the ____ of a _____ and the _____ of the adjacent X residue on another chain
N-H glycine C=O
The _________ account for the low congealing temperature of polar fish of Arctic regions
antifreeze serum glycoproteins
The _____________ was used as a consumer friendly alternative for the functional modification of egg white proteins and in particular _______, the major egg white protein.
Maillard reaction ovalbumin
If ______ proteins are hydrated, it forms a very tough elastic mass (like chewing gum)
Glutenin
_________ significantly improves the foaming, gelling, and emulsifying properties of egg white proteins
Dry heating
____________ are characterized by large numbers of lysinorlysine and desmosine crosslinks
Elastin fibers
______ is preferred as a gelling agent since it only contains trace amounts of ______, and therefore it has a good _______ stability
Egg white lipids oxidative
Pasteurization denatures the __________ network, thus resulting in the longer whip time.
ovomucin-lysozyme
The final phase of conversion of muscle to meat is referred to as ______ or ________
aging rigor resolution
______ makes up the insoluble granules in egg yolk
HDLP
______ and ______ contain sulphur in the form of cysteine and cystine
Glutenin gliadin
Gel strength and cohesiveness are ________ at pH values close to isoelectric point where net charge is minimal
minimal
When bottled or canned beer is kept below 10oC, a ____ can form because of interactions between _________ and _________ in beer
haze proteins tannins
Lipovitallin can be separated into two components, that differ by their ______ content
phosphorus
/
________, which makes up ~10% of total yolk protein, is the most highly phosphorylated protein known to date.
Phosvitin
The components of __S also comprise the soybean trypsin inhibitors
2
Animals overexpressing the inhibitor _______, postmortem protein degradation is reduced
calpastatin
__________ hydrolyses a-1-6 glycosidic bonds in starch
Pullulunase
________ causes an increase in the time period required to whip egg whites.
Pasteurization
The _____ and _____ portions of the soybean contain high levels of protein
cotyledon hypocotyl
________ readily coagulates, a process which is observed when egg white sets on heating
Ovalbumin
Protease inhibiting proteins are present in soybeans as ______ inhibitors
trypsin
_______ initiate myofibrillar degradation, resulting in release of actin, myosin, and other proteins from the ______, which may then be hydrolyzed by the ______.
Calpains sarcomere proteosome
Type I collagen is associated with _______
epimysium
The _________ occurs because the muscle cells still function adequately as long as ATP levels remain high, and hence the muscle remains pliable and undergoes lengthening when subjected to stretch.
delay phase
The role of the added salt in surimi is to ______ the _______ proteins.
solubilize myofibrillar
In skeletal muscle cells, the ubiquitous calpains tend to be concentrated in the _________
Z-discs
During the separation of ovalbumin from albumen, _________ is transported with ovalbumin into the filtrate resulting from half- saturation with ammonium sulfate.
ovotransferrin
As ATP levels continue to fall, there is a continuous increase in the number of _____ cross-bridges with _____ that are locked because of a lack of ATP.
myosin actin
________ hydrolyses a-1-4 glycosidic bonds from the non-reducing end of starch
B-amylase
Desmosine crosslinks are derived from ____ lysine chains
four
________ is a phosphoglycoprotein, with a molecular weight of about 44.5 kDa.
Ovalbumin
Ovotransferrin is also known as ________
conalbumin
The antifreeze effects of serum glycoproteins are attributed to the ______ residues as well as the _____ side chains of the peptide moiety
disaccharide methyl
Active mitochondrial respiration at a ___ ph reduces the fraction of __________ in the tissue
higher oxymyoglobin
_________ is absent in some mollusks and in Antarctic fish with colorless blood.
Hemoglobin
The ______, formerly known as __________,are proteins which possess the ability to agglutinate red blood cells.
lectins hemagglutinins
What is the consequence of reduced oxymyoglobin in the tissue?
The color of DFD meat ranges from slightly dark to extremely dark or nearly black
Lipoxygenase and polyphenol oxidase, which is responsible for ______, are _______ enzymes
browning oxidoreductase
_________ is made of an apoprotein that also binds riboflavin, a B group vitamin
Flavoprotein
During storage of eggs, ________ converts to S- a more stable form with increased resistance to denaturation.
ovalbumin
______ are usually manufactured by using alcohol to remove the soluble carbohydrates from the de-oiled soy flakes, resulting in a protein with (high/low) solubility incapable to ____ or ________
SPC low gel emulsify fat
What are the three types of glycoside hydrolases?
1) Enzymes that hydrolyze glycosidic bonds 2) Invertases 3) Lactases
_______ is a phosphorus-rich, lipid-free protein that is strongly associated with lipovitellin
Phosvitin
Separation and purification of _______ is commonly performed by half-saturating the egg white with _______, followed by the addition of ________ to ____ the pH to its isoelectric point
ovalbumin ammonium sulfate sulfuric acid lower
________ are lipid-free globular glycoproteins represent about 10% of egg-yolk total solids.
Livetins
Depletion of ATP reduces the ability of the _________ to reduce the ___________ concentration to the submicromolar range, and thereby maintain the muscle in a _____ state
calcium pump protein sarcoplasmic Ca2+ resting
________ catalyzes the oxidation of phenolic compounds (mono and/or diphenols) in the presence of _____ to give ______, which polymerize into ______ pigments (desirable or undesirable)
Polyphenol oxidase (PPO) O2 quinones melanin
A _____ cocktail from ____________ is used to partially break down glutens to reduce mixing time and making them more extensible
protease Aspergillus oryzae
_________ is the most easily heat-denatured egg protein but it is less susceptible to surface denaturation than ovalbumin.
Ovotransferrin
______ are wheat proteins that consist of a heterogeneous group of proteins, which are crosslinked by (intra/inter)molecular disulfide bonds
Glutenins inter
After the exhaustion of CrP, creatine kinase, and adenylate kinase, what becomes the dominant metabolic pathway for the generation of ATP?
Anaerobic glycolysis utilizing glycogen reserves stores in the muscle
Which amino acid is virtually absent from collagen?
Tryptophan
______ can hydrolyze all the way to glucose
Glucoamylase
___________ are produced using minimum heat and homogenization followed by spray drying, or by using a water-wash process at an (acid/base) pH to remove soluble _______, followed by neutralization
Functional soy concentrations acid sugars
As in all legumes, the bulk of soybean proteins are _______, characterized by their solubility in _____ solutions.
globulins salt
________ appear to be important in the foaming properties of albumin
Ovoglobulins
_______ binds to titin, and carries 3 unique sequences
Calpain 3
Egg white is more _____ to heat treatment when the pH is adjusted to 7.6 using lactic acid, hydrochloric acid or potassium acid tartrate.
stable
_______ is specific to skeletal muscles
Calpain 3
During mashing in the brewing process, ______ hydrolyze starch to give ______ for yeast and produce CO2 and _______
amylases maltose ethanol
________ can be heated at 100 °C under acidic conditions for long periods without any apparent changes in its physical or chemical properties.
Ovalbumin
__S also contains gamma-conglycinin, the enzymes (B-amylase and lipoxygenase), and hemagglutinins
7
The two types of soybean trypsin inhibitors are the _______ inhibitor (large), and the ________ inhibitor (small)
Kunitz Bowman-Birk
What is the major problem with all microbial sources as a source of protein?
Their high nucleic acid content, which cannot be handled by our livers in excessive amounts if consumed on a substantive scale (liver damage, gout)
In the delay phase, the level of ATP remains at >95% of the initial level, indicating that the rate at which _________ is nearly equal to the rate at which it is _________
ATP is generated consumed
If maltose is desired in corn syrup production, __________ and __________ enzymes are used
B-amylase pullulanase
________ is also present as a component of the egg-yolk proteins, differing only by its carbohydrate prosthetic group.
Ovotransferrin
_______ has a very acidic activity optima (pH 1.8), which somewhat limits its use
Pepsin
The portion of the soybean that contains the most lipids is the _____
cotyledon
Upon gelation after heating to 40-50oC, some of the water previously associated with the myofiber is apparently forced out by shrinkage of the _______, thus accounting for some of the loss of fluid observed over this temperature range.
endomysium
Following a-amylase, corn syrup production uses _______ to break down _______
glucoamylase glucose
The triple helix of collagen is also stabilized by H-bonds involving the _______ residues
hydroxyproline
The enzyme ______ has served as an indicator for the adequacy of the heat treatment given to soybean meal
urease
______ are calcium-activated proteases that are most active in the _____ pH range and are regulated by a variety of factors, including calcium, phospholipids, and calpastatin, a widely distributed calpain-specific protein inhibitor.
Calpains neutral
What happens initially with the cessation of blood flow that occurs at slaughter? How long does this last?
Myofibers utilize the oxygen bound to myoglobin to support aerobic metabolism (5 minutes)
Elastic lacks ______ and _______ AA
hydroxyproline hydroxylysine
_______ cause rapid and complete loss of the _____ owing to the degradation of troponin-T, titin, and nebulin as well as other minor proteins closely associated
Calpains Z-discs
Premature browning may occur as a result of the greater sensitivity of _______ and ________ to thermal denaturation as compared to __________
metmyoglobin oxymyogloin deoxymyoglobin
The addition of _______ in surimi further enhances the gel-forming abilities
paramyosin
The shrinkage of the __________ generates a substantial force that expels a large amount of fluid from the myofibers in the second phase as compared to the first phase.
perimysial fibers
Unlike calpains, _______ are maximally active at the _____ pHs characteristic of meat in the ______ phase
cathepsins acidic resolution
Corn syrup production starts with _________ to break _____ and ___________ to smaller units
a-amylase amylose amylopectin
The main content of protein in soy is found in storage sites called ________ or __________, which are subcellular structures that range in diameter from 2 to 20 um.
protein bodies aleuronic grains
The soybean storage proteins were extracted and characterized for the first time by ______ & ______ in 1898, and they named the extracted protein ______.
Osborne Campbell glycinin
The ________ group of collagen are stabilized and strengthened by the intra and intermolecular covalent crosslinks
striated and fibrous
The main AA in elastin is ____, and large amounts of _______ are also found
glycine proline, alanine, nonpolar aliphatic AA
Fish with dark-colored flesh have more free ______ than fish with light-colored flesh
histidine
______ is a wheat protein that requires alcohol for solubilization
Gliadin
________ hydrolyses a-1-4 and a-1-6 glycosidic bonds in starch
Glucoamylase
At ____ ionic strength or at pH values near the pI, proteins aggregate to from a turbid gel composed of random aggregates.
high
__S is a dimer of glycinin
15
During the ___________, partial degradation of the structure of the myofilament framework by endogenous _______ enzymes occurs.
resolution phase proteolytic
________ hydrolyze the methyl ester linkages of pectin
Pectin methyl esterase
__________ have almost equal ability to form cheese clots like chymosin
Fungal proteases
________ is a hydrophobic prolamine
Gliadin
_______ consists of heterogeneous group of proteins which (are/are not) crosslinked, and contain extensive (intra/inter)molecular disulfide bonds and free SH groups
Gliadin are not intramolecular
The second step in the gelation of surimi is the formation of __________, characterized by the conversion of the loose network to an ordered, non-transparent gel that is more cohesive and elastic
kamaboko
Fish muscle tissue has a high content of ______, which is derived from _____, but lacks a ______ group
taurine cysteine carboxyl
___________ are likely to be involved in restoring elastin fibers to their original shape and size following deformation
Desmosine
It is custom to characterize soybean protein fractions by their _________
sedimentation constants
______ is a strongly basic minor albumen protein
Avidin
__S is highly heterogeneous
7
The denaturation temperature of albumen proteins is highest in ________, and lowest in ________
ovalbumin ovotransferrin
___-lipovitellin (0.48% phosphorus), and ____-lipovitellin (0.27 phosphorus)
a f
Apart from papain, other popular tenderizing enzymes are _____ (from figs), ______ (from pineapple) and microbial proteases
ficin bromelain
_______ forms the lipovitellenin fraction
LDLP
_______ can be used to clear turbidity (chill haze) in beer
Papain
_______ are wheat proteins that are soluble in dilute alkali or acid
Glutenin
Type I, III, and some Type V is associated with the _______
perimysium
_______ contributes to the formation of S-S bonds in gluten in dough, without having to add chemical oxidizers
Lipoxygenase
Glucose isomerase converts an _______ to a __________
aldose ketose
The main portion of the soybean is the _______
cotyledon
The ______ may last up to 12 hours
delay phase
A _____ increase in toughness occurs over the range of 40- 50 °C, attributed to thermal denaturation of ___ and ___, which shrink and form a ____ within the myofiber that accounts for the increased toughness.
sharp actin myosin gel
Ovomucoid can be precipitated from albumen after the removal of ______ and ______ by complete saturation with _______ or by the addition of excess _____.
ovalbumin ovotransferrin ammonium sulfate alcohol
Lysozyme has optimum activity for ______ foods
low-acid
Among the egg-white proteins, ______ is unique in its resistance to heat coagulation.
ovalbumin
Paramyosin is a protein that is similar to ______ that is present in the ____ filaments of all invertebrates
myosin thick
_______ is added when clarity is desired (ex: apple juice)
Pectin methyl esterase
