Benders'dictionary of nutrition and food technology

399initial product of protein glycation to the advanced glycationend-product); potentially useful in preventing the adverse effectsof poor glycaemic control in diabetes mellitus.pyridoxal, pyridoxamine, pyridoxine See vitamin B 6 .4-pyridoxic acid The main urinary metabolite of vitamin b 6 .pyridoxyllysine A schiff base formed by condensation betweenpyridoxal and the ε-amino group of lysine in proteins. Rendersboth the vitamin b 6 and the lysine unavailable, and also hasantivitamin b 6 antimetabolic activity.pyrimidines Nitrogenous bases that occur in nucleic acids,cytosine,thymine and uracil.PYRIMIDINESpyrithiamin Antimetabolite of thiamin, used in experimentalstudies of vitamin b 1 deficiency; it inhibits thiamin pyrophosphokinase(EC 2.7.6.2) and competes for uptake across theblood–brain barrier, accumulating in the central nervous system.See also oxythiamin.pyrocarbonate See diethyl pyrocarbonate.pyrosis Alternative name for heartburn (USA). See indigestion.pyrroles Derivatives of five-membered heterocyclic compounds(C 4 H 4 NH) that impart a ‘burnt’ flavour to foods; mainly formedby the maillard reaction.pyruvic acid An intermediate in the metabolism of carbohydrates,formed by the anaerobic glycolysis of glucose. It maythen either be converted to acetyl CoA, and oxidised throughthe citric acid cycle or be reduced to lactic acid. The oxidationto acetyl CoA is thiamin dependent, and blood concentrationsof pyruvate and lactate rise in thiamin deficiency.QQPM Quality protein maize.QUAC stick Quaker arm circumference measuring stick. A stickused to measure height which also shows the 80th and 85th