Physiologically active nitrogen compounds

PORPHYRIN. Any of several physiologically active nitrogenous compounds occurring widely in nature. The parent structure is comprised of four pyrrole rings, shown in 1, II, III. and IV in Fig, 1, together with... 

Physiologically active nitrogeneous organic compounds. Synthesis of morphine-type analgesics... 

Alkaloid A physiologically active polycyclic compound containing nitrogen, often in a heterocycle—such as cocaine. 

Alkaloids are physiologically active nitrogen-containing compounds produced by plants. The term alkaloid refers to the alkali-like or basic characteristics we have seen for amines. Certain alkaloids are used in anesthetics, in antidepressants, and as stimulants, and many are habit forming. 

Alkaloids are extremely difficult to define because they do not represent a homogeneous group of compounds from either the chemical, biochemical or physiological viewpoint. All do occur in plants, but some are found in animals, and practically all have been reproduced in the laboratory by chemical synthesis. Most possess basic properties due to the presence of an amino nitrogen, and many, specially thoses pertinent to pharmacy and medicine, possess marked physiological activity. 

Caffeine belongs to a large class of compounds known as alkaloids. These are of plant origin, contain basic nitrogen, often have a bitter taste and complex structure, and usually have physiological activity. Their... 

Chemistry provides a definition of alkaloids in purely chemical terms. Chemists stress that alkaloids are any group of complex heterocyclic nitrogen compounds, which have strong physiological activity, are often toxic, and retain their own basic chemical properties. It is also stated that there are a few exceptions to this definition.Another chemical definition states only that alkaloids are nitrogen-containing compounds derived from plants and animals. Later, chemists stressed that alkaloids were bio-... 

The physiological significance of an increase in the activity of cytosolic isoforms may relate to metabolic changes associated with senescence. During senescence there is breakdown of starch, nitrogenous compounds and membrane lipids hence the increase in cytosolic isoforms. GS assimilates NH3 from degradation of cellular (and chloroplastic) proteins into amides for translocation. PGK would not only assimilate triosephosphates for export but (along with DHAP reductase) would be involved in the increased respiration and metabolic breakdown associated with senescence. 

---