Term
| How are enzymes targeted to lysosomes? |
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Definition
| N-linked oligosaccharide Mannose-6-phosphate |
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Term
| This is the enzyme that transfers GlcNAc phosphate from UDP-GlcNAc to an enzyme destined for the lysosome. |
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Definition
| N-acetyl-glucosamine (GlcNAc) phosphotransferase |
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Term
| What protein removes GlcNAc from a protein that will have the M-6-p N tail? |
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Definition
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Term
What ensures lysosomal enzymes targeted to
vesicles that are ultimately directed to the lysosomes? Where are they found? |
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Definition
Mannose-6-phosphate receptor
They are found on the lumenal trans golgi, also some are found on the external plasma membrane (life isn't perfect some are accidentally secreted) |
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Term
| What causes the phosphorylated enzyme to dissociate from its receptor, and the receptor recycles back to the Golgi? |
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Definition
| low pH of the clathrin sorting vesicle |
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Term
| What simple test can be done to determine if a person has I-cell disease? |
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Definition
| Blood test, will see 10 to 20 fold increase of of hexosaminidase, iduronate sulfatase, and aryl sulfatase A activity in serum. These enzymes are suppose to be in the lysosome |
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Term
| Proteins that are secreted from the cell are more likely to have __________ for extra stability? |
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Definition
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Term
| As insulin is processed in the golgi, it can bind which inorganic molecule? |
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Definition
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Term
| How many insulin molecules come together to bind zinc? |
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Definition
| 6 (hexamer) known as zinc insulin crystals |
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Term
| What is another name for insulin in the hexameric form? |
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Definition
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Term
| Lente and ultralente insulin depend on changes in the ______________. |
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Definition
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Term
| Analogues of insulin depend on changes in the ___________. |
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Definition
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Term
| In lispro insulin, what is the change that has been induced and what does it do and how does lispro differ? |
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Definition
In the C- terminus flip Lys-Pro-Tyr to Pro-Lys-Tyr.
This disrupts the beta sheet that will form here. the beat sheet. holds the dimeric insulin together.
Now its fast acting insulin. |
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Term
| If insulin can't form dimers its even less likely to form... |
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Definition
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Term
| T and R states of insulin are associated with ligand binding to 2 allosteric binding sites, they are... |
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Definition
| phenolic pocket and the His B10 Zn2+ anion site |
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Term
| What binds in one of the allosteric sites of insulin, stabilizing the R form of hexameric insulin and creating ultralente (long lasting insulin-duration of action is long lasting). |
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Definition
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Term
| The last 9 residues of the B-chain of insulin go from________ to __________, when going from the T state to the R state. |
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Definition
| these residues go from an extended conformation in the T-state to an α-helical conformation in the R-state |
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Term
| the term Rf in T3R3f denotes “frayed” where |
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Definition
| residues B1–B3 are found in a non-helical conformation |
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Term
| Does the T or R form of insulin have the phenolic pocket? |
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Definition
| R form- note this pocket is hydrophobic |
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Term
| Helix side chains making up the lining of the tunnel in the R form are> |
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Definition
| Phe B1, Asn B3, and LeuB6 |
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Term
| Zinc is coordinated to _______ at the botom of the tunnel in the R form of insulin |
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Definition
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Term
| Low pH favors the __ form of insulin? |
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Definition
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Term
| in the T3R3 conformation MPO binds to... |
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Definition
| the phenolic pocket created by the movement of Phe B1 |
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Term
| In the T6 conformation MPO binds at |
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Definition
| dimer-dimer interfaces of the T6 hexamer via interacting amino acids Leu A13, Tyr A14, Glu A17 |
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