lab 3 metabolic maps, Summaries of Biochemistry

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Lab 3: Serum Lipids

Clinical applications of lipoproteins:

• Patient data
• Health-risk for stroke/heart disease

TG and CE (inside) PL Cholesterol Apolipoprotein

Structure of circulating serum lipoproteins

Apolipoproteins

• help “solubilize” lipids
• receptor recognition ( targeting ; uptake and degradation) Outer mono layer of mostly PL & chol ( amphipathic ) transporting H 2 O-insoluble triglycerides in blood Core of TG & CE ( nonpolar ) glob of fat

Xanthomas

https://en.wikipedia.org/wiki/Xanthoma Cholesterol deposits under the skin

Inert silicone gel Collect blood Allow to clot Spin to sediment cells & clot gel plug Cells and clot Serum

Blood

Blood serum

CH 3 CH 3 l CH - CH 2 - CH 2 - CH 2 - CH CH 3 CH 3 CH 3 HO CH 3 CH 3 l CH - CH 2 - CH 2 - CH 2 - CH CH 3 CH 3 CH 3 O Cholesterol oxidase

+ H 2 O 2

Cholesterol Cholest- 4 - en- 3 - one Cholesterol + O 2 Cholest- 4 - en- 3 - one + H 2 O 2 Cholesterol oxidase Cholesterol + O 2 Cholest- 4 - en- 3 - one + H 2 O 2 Cholesterol oxidase

+ O 2

Cholesterol assay – step 2

(2) Oxidize free cholesterol to form H 2 O 2 (hydrogen peroxide)

4 H 2 O 2 H 2 O 2 + 4-aminophenazone + phenol o-quinoneimine dye + 4 H 2 O (colored compound) Peroxidase

Peroxidase 2H 2 O 2 OH l OH l N CH 3 - N ll O CH 3 NH 2

CH 3 - N N l O CH 3 N ll ll O CH 3 - N N l O CH 3 N ll ll O 4 H 2 O 2 H 2 O 2 + 4-aminophenazone + phenol o-quinoneimine dye + 4 H 2 O (colored compound) Peroxidase

Peroxidase 2H 2 O 2 OH l OH l N CH 3 - N ll O CH 3 NH 2

CH 3 - N N l O CH 3 N ll ll O CH 3 - N N l O CH 3 N ll ll O

Cholesterol assay – step 3

(2) Convert H 2 O 2 (hydrogen peroxide) to a colored compound

• What is the biological function of chylomicrons? VLDL? LDL? HDL? In what location is each of the serum lipoproteins formed? What is it carrying? Where is it delivering its cargo? What is the half-life of the lipoprotein?
• Why is the complex called a lipoprotein? What are the components of the different lipoproteins? Relative densities? Relative sizes?
• Why are lipoproteins needed? What forces drive the formation of lipoproteins? Are all fatty acids and triglycerides transported by lipoproteins?

• Under what conditions is the blood sample drawn for assaying blood cholesterol levels? Why is that significant? What lipoproteins are expected to be present in the blood serum? Is there a way to tell if the patient was actually in a fasting state? How are the different lipoproteins separated for assaying? Which lipoproteins can be directly assayed?

Using the tables, address the following questions: (1) Does ethnicity impact cholesterol levels? (2) Are there differences in cholesterol levels between males and females? (3) Do cholesterol levels change with age?

• What do you think is the best way to assess risk for CHD? Use total cholesterol? HDL cholesterol? Ratio of total cholesterol to HDL cholesterol? Something else?

Look at the patient data for the 5 patients and rank the patients from lowest risk for CHD to highest risk for CHD using the charts in L DOCU.