U9 Flashcards
true or false: egg white is high in carb and lipid content
false! 1%
main 4 protein constituents in albumin
- ovalbumin
- ovotransferrin
- ovomucoid
lysozyme
what kind of protein is ovalbumin
phosphoglycoprotein
what is special about ovalbumin that the other egg white proteins dont have
free sulfhydryl group
how stable is ovalbumin
not very stable - easily coagulated in heat and easily denatures when exposed to new surfaces
what are 2 important functions of ovalbumin
stabilizes foam
gelling agent
what kind of gel does ovalbumin create (in heat)
transparent, turbid gel
what process is used to purify ovalbumin
- half-saturate with ammonium sulfate
- filter
- sulfuric acid lowers the pH to pL 4.6-4.8
- recrystallizations
what kind of protein is ovotransferrin
iron-binding transferrin
what kind of prosthetic group does ovotransferrin have
carbohydrate
what allows ovotransferrin to have bacteriostatic and bactericidal avticities
iron-sequestering properties
how to purify ovotransferrin
- half-saturate with ammonium sulfate
- precipitate with more ammonium sulfate or alcohol fractionation
or ion exchange chromotography
what is the most easily heat-denatured egg protein
ovotransferrin
wht kind of protein is ovomucoid
glycoprotein
what is the quaternary structure of ovomucoid like
3 homogenous domains crosslinked
where are the polysacchridees of the ovomucoid
attached to Asp
how are ocomucoids purified
complete saturation with ammonium sulfate or adding excess alcohol
what kind of protein is lysozyme
bacteriolytic enzyme
what is the function of lysozme
Catalyzes hydrolysis of glycosidic links between NAM and NAG in bacterial cell walls
optimal ph activity for lysozyme
5.3-6.4
what funcitonal characterisitc is special about lysozyme
heat stable and stable during drying
what is avidin
basic protein
what is ovoglobulin
foaming protein
what is ovoinhibitor
inhibits trypsin, chymotrypsin, elastase
what is flavoprotein
binds riboflavin
what does yolk act like in food and why
lipid - it has high proportions of phosphoplipids and lipoproteins
what function does yolk have
emulsifier
4 classes of yolk proteins
Lipoproteins - LDL and HDL
lipid-free globular proteins
phosphoproteins
minor proteins
what is heat coagulation
thermal denaturation and aggregation of proteins in albumen and yolk
what is denaturation
breaking of h-bonds, uncoiling of peptide chains, exposure of reactive groups
what do proteins form when denatured and with what bonds
aggregate to form a 3D gel network via h-binds, electrostatic links, disulfide links