Biochemistry – Notes

Polysaccharides:

• Hyaluronic acid:

• Structure: Composed of beta-D-glucuronic and N-acetyl-beta-D-glucosamine monomers.

• Linkage: 1-3 within monomers, 1-4 between monomers.

• Number of monomers: 250-25,000 units.

• Role: Found in the vitreous humor of the eye.

• Chondroitin sulfate:

• Structure: Composed of beta-D-glucuronic and N-acetyl-beta-D-galactosamine 4-sulfate monomers.

• Note: Galactosamine, not glucosamine.

• Number of monomers: 50-1000 units.

• Keratan sulfate:

• Structure: Composed of beta-D-galactose and N-acetyl-D-glucosamine 6-sulfate monomers.

• Heparin:

• Structure:

• According to older textbooks: N-sulfo-D-glucosamine 6-sulfate and alpha-D-glucuronate 2-sulfate.

• According to newer textbooks: D-glucosamine 2,6-disulfate and D-glucuronate 2-sulfate/L-iduronate 2-sulfate.

Purine biosynthesis:

• Origin of atoms in the purine ring:

• N1: Aspartate

• C2, C8: Formic acid

• N3, N9: Glutamine

• C4, C5, N7: Glycine

• C6: CO2

Hormones:

• Gonadotropin family hormones (HCG, LH, FSH, TSH):

• Structure:

• Alpha chain: 92 amino acids (identical)

• Beta chain: Species-specific

• Number of amino acids in the beta chain:

• HCGb: 145 aa

• LH: 121 aa (+92): Horizontal S shape

• FSH: 117 aa, W shape

• TSH: 112 aa, M shape

Note:

• This is a brief summary of notes.

• For a deeper understanding, refer to specialized literature.