Category: P

  • Protein C

    A vitamin-K dependent zymogen present in the blood, which, upon activation by thrombin and thrombomodulin exerts anticoagulant properties by inactivating factors Va and VIIIa at the rate-limiting steps of thrombin formation. An anticlotting (glyco) protein that prevents post-operative arterial clot formation when administered intravenously. May be synergistic (in its anticlotting effect) with tissue plasminogen activator…

  • Protease inhibitors

    Compounds which inhibit or antagonize biosynthesis or actions of proteases (endopeptidases). Compounds that inhibit the protein degradative action of the protease enzymes. Class of anti-HIV (Human Immunodeficiency Virus) drugs designed to inhibit the enzyme protease and interfere with virus replication. Protease inhibitors prevent the cleavage of HIV precursor proteins into active proteins, a process that…

  • Protease

    Proteinase (= any enzyme that catalyses the splitting of interior peptide bonds in a protein). An enzyme that catalyzes the hydrolytic cleavage (breakdown) of proteins. By analogy, the enzyme breaks the link (peptide bond) holding a chain together. Proteases represent a whole class of protein-degrading enzymes. A digestive enzyme which breaks down protein in food…

  • Propyl gallate

    Antioxidant for foods, fats, oils, ethers, emulsions, waxes, and transformer oils. A substance with antioxidant properties that is frequently employed in combination with BHA and BHT to impede the oxidation of fats, thus mitigating the development of rancidness.    

  • Propolis

    Propolis

    Resinous substance obtained from beehives; contains many different substances which may have antimicrobial or antimycotic activity topically; its extracts are called propolis resin or balsam. Synonyms: bee bread; hive dross; bee glue. Resin collected by honeybees, used as a local antibiotic and antifungal. It can be used to help treat inflammation, burns, canker sores, and…

  • Prophase

    The first phase of cell division, in which the chromosomes become visible, the nucleus starts to lose its identity, the spindle appears, and the centrioles migrate toward opposite poles. An early stage in meiosis during which the chromosomes are dispersed throughout the nucleus and are doubled longitudinally. The first stage of mitosis when the chromosomes…

  • Promotor

    In an operon, a nucleotide sequence located at the operator end which contains all the signals for the correct initiation of genetic transcription by the RNA polymerase holoenzyme and determines the maximal rate of RNA synthesis.  

  • Promoter

    A chemical substance that increases the activity of a carcinogenic process. DNA sequence within a gene that controls the start of transcription for that gene. The region on DNA to which RNA polymerase binds and initiates transcription. The promoter “promotes” the transcription (expression) of that gene. A region of DNA (deoxyribonucleic acid) which lies “upstream”…

  • Proline

    A non-essential amino acid that is synthesized from glutamic acid. It is an essential component of collagen and is important for proper functioning of joints and tendons. An amino acid found in proteins, especially in collagen. Proline is a nonessential amino acid used in the formation of the body’s proteins. It is particularly important, along…

  • Prokaryote

    Unicellular organism having a less complex structure than a eukaryote; it’s characterized by the absence of a nucleus and by having the genetic material in the form of simple filaments of DNA. Single-cell organisms. Organism containing cells without nuclei, the nuclear material being scattered throughout the cell. Bacteria, blue-green algae, and certain other microorganisms are…