Biochemistry

The Protein Buffer Systems The protein buffers are very important in the plasma and the intracellular fluids but their concentration is very low in cerebrospinal fluid, lymph and interstitial fluids. The proteins exist as anions serving as conjugate bases (Pr − ) at the blood pH 7.4 and form conjugate acids (HPr) accepting H+ .  They have the capacity to buffer some H2CO3  in the blood.…

The input to fatty acid synthesis is acetyl-CoA, which is carboxylated to malonyl-CoA. The ATP-dependent carboxylation provides energy input. The CO2 is lost later during condensation with the growing fatty acid. The spontaneous decarboxylation drives the condensation.   fatty acid synthesis acetyl-CoA + 7 malonyl-CoA + 14 NADPH → palmitate + 7 CO2 + 14 NADP+ + 8 CoA ATP-dependent synthesis of malonate: 8 acetyl-CoA + 14 NADPH + 7 ATP &rarr…

Sphingosine is an amino alcohol present in sphingomyelins (sphingophospholipids).  They do not contain glycerol at all. Sphingosine is attached by an amide linkage to a fatty acid to produce ceramide. The alcohol group of sphingosine is bound to phosphorylcholine in sphingomyelin structure. . Sphingomyelins are important constituents of myelin and are found in good quantity in brain and nervous tissues.…

Glycolysis Pathway   The reactions of Glycolysis take place in the cytosol of cells. Glucose enters the Glycolysis pathway by conversion to glucose-6-phosphate. Initially, there is energy input corresponding to cleavage of two ~P bonds of ATP.  1. Hexokinase catalyzes:  glucose + ATP → glucose-6-phosphate + ADP ATP binds to the enzyme as a complex with Mg++. The reaction catalyzed by Hexokinase is highly spontaneous  &nb…

BIOLOGICAL BUFFER SYSTEMS  Cells and organisms maintain a specific and constant cytosolic pH, keeping biomolecules in their optimal ionic state, usually near pH 7. In multicelled organisms, the pH of the extracellular fluids (blood, for example) is also tightly regulated. Constancy of pH is achieved primarily by biological buffers : mixtures of weak acids and their conjugate bases  Body fluids and their principal buffers Body fluids   …