This study is a Phase I single ascending dose clinical trial in which healthy adult volunteers were administered single oral doses of GenSci144 tablets at different levels. It was conducted using a randomized, double-blind, placebo-controlled design, primarily to evaluate the drug's safety and tolerability, while also exploring its pharmacokinetic and pharmacodynamic characteristics in the body, providing a basis for subsequent clinical use in the treatment of phenylketonuria.

Inclusion Criteria:

• Healthy men and women aged 18 to 45, with at least 3 people of the same gender in each group.
• BMI 19~26 kg/m², men weigh ≥50 kg, women ≥45 kg.
• Voluntarily sign the informed consent form, fully aware of the research risks and procedures.
• Use reliable contraception for 3 months after the last dose, no plans for pregnancy or sperm/egg donation.

Exclusion Criteria:

• A family history of sudden death and serious neuropsychiatric disorders.
• Major underlying conditions like gastrointestinal absorption problems, chronic liver, kidney, heart, and endocrine diseases.
• Liver function, kidney function with eGFR<90, abnormal QTc interval, positive for various infectious diseases.
• Drug allergies, drug abuse, recent participation in other clinical trials.
• Drinking alcohol, smoking, taking grapefruit/amino acid supplements, and having a chaotic routine during the screening period.
• Pregnant or breastfeeding women, people who can't tolerate blood draws or get faint from needles.