📖 Biochemistry
Cardiac Enzymes: Organ-Specific Markers
Biochemistry| Enzyme | Clinical Use | Timing |
|---|---|---|
| Troponin I/T | Gold standard for myocardial infarction | Rises in 3–6 hrs, peaks at 12–24 hrs |
| CK-MB | Specific to cardiac muscle damage | Rises in 4–6 hrs, peaks at 24 hrs |
| LDH (Isoenzyme 1) | Used historically for MI diagnosis | Peaks at 48–72 hrs |
Troponins remain elevated for up to 10 days—ideal for late diagnosis.
Basic characteristics of enzymes
BiochemistryThe basic characteristics of enzymes includes
(i) Almost all the enzymes are proteins and they follow the physical and chemical reactions of proteins (ii) Enzymes are sensitive and labile to heat
(iii) Enzymes are water soluble
(iv) Enzymes could be precipitated by protein precipitating agents such as ammonium sulfate and trichloroacetic acid.
HORMONES
BiochemistryHORMONES
A hormone is a chemical that acts as a messenger transmitting a signal from one cell to another. When it binds to another cell which is the target of the message, the hormone can alter several aspects of cell function, including cell growth, metabolism, or other function.
Hormones can be classified on three primary ways as following:
1. Autocrine: An autocrine hormone is one that acts on the same cell that released it.
2. Paracrine: A paracrine hormone is one that acts on cells which are nearby relative to the cell which released it. An example of paracrine hormones includes growth factors, which are proteins that stimulate cellular proliferation and differentiation.
3. Endocrine: An endocrine hormone is one that is released into the bloodstream by endocrine glands. The receptor cells are distant from the source. An example of an endocrine hormone is insulin, which is released by the pancreas into the bloodstream where it regulates glucose uptake by liver and muscle cells.
Glycogen Storage Diseases
BiochemistryGlycogen Storage Diseases are genetic enzyme deficiencies associated with excessive glycogen accumulation within cells.
- When an enzyme defect affects mainly glycogen storage in liver, a common symptom is hypoglycemia (low blood glucose), relating to impaired mobilization of glucose for release to the blood during fasting.
- When the defect is in muscle tissue, weakness and difficulty with exercise result from inability to increase glucose entry into Glycolysis during exercise.
Various type of Glycogen storage disease are
|
Type |
Name |
Enzyme Deficient |
|
I |
Von Geirke’s Disease |
Glucose -6-phosphate |
|
II |
Pompe’s Disease |
(1, 4)glucosidase |
|
III |
Cori’s Disease |
Debranching Enzymes |
|
IV |
Andersen’s Disease |
Branching Enzymes |
|
V |
McArdle’s Disease |
Muscles Glycogen Phosphorylase |