Melanin Biochemistry: Eumelanin Biosynthesis From Tyrosine and Phenylalanine

The video explains the synthesis and biochemistry of melanin, focusing on eumelanin. It covers the role of melanocytes and melanosomes in protecting DNA from UV-induced mutations. The synthesis begins with tyrosine, which can be derived from phenylalanine. Key enzymes like tyrosinase and DOPA Chrome tautomerase are crucial in the synthesis process. The video also discusses the implications of tyrosinase deficiency, leading to conditions like albinism.

What is the primary function of melanin in the skin?

• To protect DNA from UV-induced mutations

• To regulate body temperature

• To aid in vitamin D synthesis

• To provide color to the skin

Which type of melanin is responsible for the blackish-brownish tint in the skin?

• Neuromelanin

• Eumelanin

• Allomelanin

• Pheomelanin

Which amino acid can be converted into tyrosine for melanin synthesis?

• Methionine

• Phenylalanine

• Tryptophan

• Leucine

What is the role of tyrosine transporters in melanin synthesis?

• They convert tyrosine into DOPA

• They transport tyrosine into the melanosome

• They synthesize tyrosine from phenylalanine

• They polymerize melanin

Which enzyme is primarily responsible for converting tyrosine into DOPA?

• DOPA Chrome tautomerase

• Phenylalanine hydroxylase

• Tyrosinase

• DOPA decarboxylase

What is the main branch point in eumelanin synthesis?

• DHI

• DHICA

• DOPA

• DOPA quinone

What happens to DOPA Chrome in a non-enzymatic reaction?

• It converts to DOPA quinone

• It converts to DHICA

• It converts to DHI

• It converts to melanin

What is the consequence of a tyrosinase deficiency?

• Increased melanin production

• Enhanced UV protection

• Darker skin pigmentation

• Albinism

Why is tyrosinase considered the most important enzyme in melanin synthesis?

• It polymerizes melanin directly

• It is involved in the initial step of converting phenylalanine to tyrosine

• It is responsible for the transport of tyrosine into the melanosome

• It catalyzes multiple steps in the synthesis of melanin

What is the biochemical cause of albinism?

• Excessive production of pheomelanin

• Deficiency of tyrosinase

• Overactive melanosomes

• Lack of phenylalanine