Which enzyme is responsible for the conversion of methionine to homocysteine, and what condition is associated with elevated levels of homocysteine?

A Methionine synthase, and elevated homocysteine levels are associated with Atherosclerosis
B Cystathionine beta-synthase, and elevated homocysteine levels are associated with Homocystinuria ✓
C Methionine adenosyltransferase, and elevated homocysteine levels are associated with Alzheimer's disease
D S-adenosylhomocysteine hydrolase, and elevated homocysteine levels are associated with Cardiovascular disease

Explanation

Cystathionine beta-synthase is the enzyme responsible for the conversion of methionine to homocysteine. Elevated levels of homocysteine are associated with Homocystinuria, a genetic disorder that affects the metabolism of amino acids.

Source

OMIM Database
Enzymes in Disease Biochemistry Amino Acid Metabolism Medium MEDICAL Confidence: high