proteiinilla

Protein, or proteiinia in Finnish, is a large biomolecule built from amino acids linked by peptide bonds. The sequence of amino acids encodes the protein’s properties, and the chain folds into higher-order structures that determine function. Proteins can have one chain or multiple subunits and may form complexes. Their stability and conformation depend on environmental conditions such as pH and temperature. Proteins play roles in virtually all cellular processes.

The functions of proteins are diverse: enzymes catalyze chemical reactions; structural proteins (collagen, keratin) provide support; transport proteins carry molecules (hemoglobin); antibodies defend against pathogens; receptors and signaling molecules coordinate cellular responses; hormones such as insulin regulate metabolism. Proteins are synthesized by ribosomes using mRNA templates in a process called translation, and they fold with assistance from chaperone proteins. Denaturation or misfolding can impair function and is implicated in diseases such as amyloidoses and some neurodegenerative disorders.

Dietary protein provides amino acids, of which nine are essential for most adults. Complete proteins from animal sources (meat, dairy, eggs) contain all essential amino acids; many plant proteins are incomplete, though combinations can ensure adequacy. Protein quality is assessed by metrics like PDCAAS and DIAAS, and daily intake guidelines commonly recommend about 0.8 g per kilogram of body weight for adults, higher for athletes or during aging. The body recycles amino acids through protein turnover; excess protein can be used for energy or stored as fat.