代谢的先天性错误: Refsum 疾病

Phenylketonuria (PKU) is a protein metabolism disorder characterized by high blood levels of the amino acid phenylalanine. This results from a mutation in the gene responsible for phenylalanine hydroxylase, an enzyme that converts phenylalanine into tyrosine. When this enzyme is deficient, phenylalanine builds up in the blood, leading to symptoms such as vomiting, rashes, seizures, growth deficiency, and severe mental retardation. An early diagnosis and a diet restricting phenylalanine intake...

Cells contain membrane-bound organelles called peroxisomes that oxidize organic molecules by transferring hydrogen atoms to oxygen, producing hydrogen peroxide. Peroxisomes enzymatically convert the released hydrogen peroxide into water and oxygen.
Peroxisomal Protein Import:
Peroxisomes lack the genetic machinery required to code for their own proteins. Hence, most peroxisomal membrane, lumenal and transmembrane proteins are synthesized in the cytoplasm or ER and transported to the peroxisome...

Proteins are broken down into amino acids during digestion. Unlike fats and carbohydrates, which are stored for later use, proteins are not. Instead, amino acids are either used to produce ATP through oxidation or contribute to the creation of new proteins for the growth and repair of the body. Any surplus amino acids from the diet are converted into glucose or triglycerides rather than excreted.
Amino acids play various roles in the body once they are absorbed into cells. They are restructured...

Smooth endoplasmic reticulum or smooth ER is a sub-organelle with specialized functions in animal cells and plant cells. It is often associated with the tubule morphology of the endoplasmic reticulum.
The ER provides optimal conditions for synthesizing steroid hormones and lipids, such as phospholipids and triglycerides. Traditionally, lipid metabolism was considered to be a smooth ER function. However, there is no direct evidence to prove that rough ER is completely excluded from lipid...

Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of Life
Proteins are...

Carbohydrate metabolism is a fundamental biochemical process that ensures a constant supply of energy to living cells. The most important carbohydrate is glucose, which can be broken down via glycolysis to enter into the Krebs cycle and eventually lead to the production of ATP through oxidative phosphorylation.
Glucose transport into cells is facilitated by a family of transport proteins called GLUT (Glucose Transporters). GLUT4 is the primary glucose transporter for insulin-stimulated glucose...