LIPIDS pt 4

• Amino acids


  Important class of organic compounds that contain both the amino (-NH2) and carboxyl (-COOH) groups
• Amino acids


  • Building block of protein
• Non-polar amino acids

  • Have non-polar R-groups or hydrophobic side chains
• Isoelectric point (pI)

  The pH at which the amino acid has no net charge
• Alanine (Ala, A) has a pI of 6.01
• Phenylalanine (Phe, F) has a pI of 5.48
• Proline (Pro, P) has a pI of 6.48
• Isoleucine (Ilsy, l) has a pI of 6.02
• Leucine (Leu, L) has a pI of 5.98
• Valine (Val, V) has a pI of 5.97
• Tryptophan (Trp, W) has a pI of 5.88
• Methionine (Met, M) has a pI of 5.74
• what are the essential amino acid/ten amino acids

  • histidine

  • methionine

  • arginine

  • trypthophan

  •thneonine

  • isoleucine

  • leucine

  • lysine

  • valine

  • phenylalanine
• must be supplied in the diet proper growth and development because either that there are no biochemical pathway available for their synthesis or the available pathway do not provide adequate amount for proper nutrition

  essential amino acids
• can be synthesized by enzyme catalyzed reaction

  essential amino acids
• The amino acid which cannot be synthesized by the body and therefore need to be supplied through the diet

  essential amino acids
• cannot be provided by the body but must be provided


  essential amino acids
• what are the sources of essential amino acids


  • casein

  • zein

  • gliadin

  • rice

  • legumes
• • Amino acids contains acidic (COOH) and basic (NH2) and basic (NH2)

  • Amino acids are usually ionized at physiologic pH

  • Therefor, amino acids have amphoteric properties :

  • In acidic medium; the amino acid is positively charged, so it behaves as a base (proton acceptor
  • In alkaline medium; the amino acid is negatively charged, so it behaves as an acid (proton donor )
• complete protein from milk

  casein
• corn protein but deficient in lysine, trp

  zein
• from wheat but deficient in lysine

  gliadin
• lacks lysine and trypthophan

  rice
• low in methionine and cysteine

  legumes
• Isoelectric point (pl)


  The pH at which the amino acid has no net charge
• asparagine (Asn, N) has a pI of 5:41
• glutamine (Gln, Q) has a pI of 5.65
• cycteine (Cys, C) has a pI of 5.07
• tyrosine (Tyr, Y) has a pI of 5.66
• serine (Ser, S) has a pI pl of 5.68
• aspartic acid (Asp, D) has a pI of 2.77
• glutanemic acid (Glud, E) has a pI of 3.22
• arginine (Arg, R) has a pI of 10.78
• histidine (His, H) has a pI of 7.59
• lysine (Lys, K) has a pI of 9.74
• asymmetric except in glycine

  alpha-carbon
• optically active


  alpha-carbon
• example of configuration


  alpha-carbon
• example of dipolar nature

  zwitterions
• explains their physical properties such as being solid with high melting point


  zwitterions