Definition of protein in US English:



  • 1Any of a class of nitrogenous organic compounds that consist of large molecules composed of one or more long chains of amino acids and are an essential part of all living organisms, especially as structural components of body tissues such as muscle, hair, collagen, etc., and as enzymes and antibodies.

    • ‘The 75-kD fusion protein was purified four times by affinity binding to an amylose resin.’
    • ‘The tertiary structure of myoglobin is that of a typical water soluble globular protein.’
    • ‘Much recent research has focused on identifying proteins involved in metabolism of such compounds.’
    • ‘Western blot analysis confirmed that this truncated fusion protein is expressed in yeast (data not shown).’
    • ‘The scientists have genetically engineered the animals to produce a green fluorescent protein in cells throughout the abdomen.’
    1. 1.1 Proteins collectively, especially as a dietary component.
      ‘a diet high in protein’
      • ‘I always try to make sure that whatever I eat is balanced as I like to have my greens and my protein.’
      • ‘In the latter case, you may want to add diced tofu or ham to the filling for a bit more protein.’
      • ‘There would be little rice and even less protein for the family before the rains came again in May.’
      • ‘Some postmenopausal women swear that dietary soy protein combats their hot flushes.’
      • ‘The diet does seem to help with the training as well - all that pasta, rice and pure soya protein.’
      • ‘Rice is high in protein, but these proteins are low in the essential amino acid lysine.’
      • ‘Cover half your plate with vegetables, then a quarter with carbs and a quarter with protein.’
      • ‘When there is a lot of carbohydrate in the diet, protein and fat are spared.’
      • ‘Eat either protein or starch combined with vegetables other than the potato.’
      • ‘An elemental diet is a liquid diet, made up of simple forms of protein, carbohydrates and fats.’
      • ‘As well as protein, Brazils are high in fat, which causes them to go rancid quickly.’
      • ‘If you have healthy kidneys, you can't eat enough protein to damage your kidneys.’
      • ‘Made out of lentils, beans and spices, these little balls are rich in fibre and protein.’
      • ‘Pulses such as lentils are the most important source of protein in the Indian diet.’


Mid 19th century: from French protéine, German Protein, from Greek prōteios ‘primary’, from prōtos ‘first’.