Difference between revisions of "Galactose" - New World Encyclopedia

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| OtherNames =  
 
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| Section1 = {{Chembox Identifiers
 
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| CASNo = 26566-61-0
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| CASNo = 26566-61-0
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| PubChem = 6036
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| PubChem = 6036
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| MeSHName = Galactose
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| MeSHName = Galactose
 
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| Section2 = {{Chembox Properties
 
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| Formula = C<sub>6</sub>H<sub>12</sub>O<sub>6</sub>
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| Formula = C<sub>6</sub>H<sub>12</sub>O<sub>6</sub>
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| MolarMass = 180.08
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| MolarMass = 180.08
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| MeltingPt = 167 degrees C
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| MeltingPt = 167 degrees C
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'''Galactose''' (Gal) is a six-carbon [[sugar]] and a   [[carbohydrate#Monosaccharides|monosaccharide]] that combines with [[fructose]] to form the [[carbohydrate#Disaccharides|disaccharide]] [[lactose]], forms galactose [[carbohydrate#Polysaccharides|polysaccharide]]s in [[agar]], is a component in various [[gum]]s, [[mucilage]]s, and [[pectins]], and is also present in [[sugar beets]]. As a hexose sugar, galactose has the same formula as [[glucose]], C<sub>6</sub>H<sub>12</sub>O<sub>6</sub>, but differs in the position of the [[hydroxyl]] group on carbon-4 (Bender and Bender 2005). Along with [[glucose]] and fructose, galactose is one of the three most important [[blood]] sugars in [[animal]]s. Galactose also is known as '''brain sugar''' (Houghton Mifflin 1998).  
+
'''Galactose''' (Gal) is a six-carbon [[sugar]] and a [[carbohydrate#Monosaccharides|monosaccharide]] that combines with [[glucose]] to form the [[carbohydrate#Disaccharides|disaccharide]] [[lactose]], forms galactose [[carbohydrate#Polysaccharides|polysaccharide]]s in [[agar]], is a component in various [[gum]]s, [[mucilage]]s, and [[pectins]], and is also present in [[sugar beets]]. As a hexose sugar, galactose has the same formula as glucose, C<sub>6</sub>H<sub>12</sub>O<sub>6</sub>, but differs in the position of the [[hydroxyl]] group on carbon-4 (Bender and Bender 2005). Along with glucose and [[fructose]], galactose is one of the three most important [[blood]] sugars in [[animal]]s. Galactose also is known as '''brain sugar''' (Houghton Mifflin 1998).  
  
 
Galactose is less sweet than glucose and [[sucrose]]. It is considered a nutritive [[sweetener]] because it has [[food energy]]. Galactose and glucose both play important roles in joining with [[lipid]]s to form [[glycolipid]]s and joining with [[protein]]s to form [[glycoprotein]]s. Galactolipids are a major component of the membrane [[Biological tissue|tissue]]s of plants, while galactose joined in forming the more complex [[cebroside|galactocerebroside]]s acts as an important component of membrane tissues in animal muscles and nerves.  
 
Galactose is less sweet than glucose and [[sucrose]]. It is considered a nutritive [[sweetener]] because it has [[food energy]]. Galactose and glucose both play important roles in joining with [[lipid]]s to form [[glycolipid]]s and joining with [[protein]]s to form [[glycoprotein]]s. Galactolipids are a major component of the membrane [[Biological tissue|tissue]]s of plants, while galactose joined in forming the more complex [[cebroside|galactocerebroside]]s acts as an important component of membrane tissues in animal muscles and nerves.  
  
−
Under normal conditions, the intricate coordination in the [[human body]] is remarkable, with lactose in [[food]] being broken down, via [[enzyme]]s, into glucose and galactose, and these sugars being further [[metabolism|metabolized]]. However, in rare cases (one per 47,000 births), this harmonious system is compromised by a genetic disorder, affecting an individual's ability to properly metabolize the sugar galactose. This leads to toxic levels of galactose building up in the blood, requiring the elimination of lactose and galactose from the diet. This condition is known as galactosemia.  
+
Under normal conditions, the intricate coordination in the [[human body]] is remarkable, with lactose in [[food]] being broken down, via [[enzyme]]s, into glucose and galactose, and these sugars being further [[metabolism|metabolized]]. However, in rare cases (one per 62,000 births), this harmonious system is compromised by a genetic disorder, affecting an individual's ability to properly metabolize the sugar galactose. This leads to toxic levels of galactose building up in the blood, requiring the elimination of lactose and galactose from the diet. This condition is known as galactosemia.  
  
 
==Description==
 
==Description==
 
[[Image:D-glucose.svg|100px|right|thumb|Glucose as a straight-chain. Galactose differs only in the position of the hydroxyl group on carbon-4.]]
 
[[Image:D-glucose.svg|100px|right|thumb|Glucose as a straight-chain. Galactose differs only in the position of the hydroxyl group on carbon-4.]]
−
Galactose is a six-carbon monosaccharide. As a carbohydrate, galactose belongs to that class of biological [[molecule]]s that contain primarily [[carbon]] (C) atoms flanked by [[hydrogen]] (H) atoms and hydroxyl (OH) groups (H-C-OH). As a hexose carbohydrate, galactose has the same molecular formula as glucose and fructose ([[carbon|C]]<sub>6</sub>[[hydrogen|H]]<sub>12</sub>[[oxygen|O]]<sub>6</sub>) but a different atomic arrangement. It differs from glucose only in the position of the hydroxyl group on carbon-4 (Bender and Bender 2005). (The carbons of glucose are numbered beginning with the more oxidized end of the molecule, the [[carbonyl]] group.) In other words, galactose is an epimer of glucose, having a different configuration at only one of several stereogenic centers.  
+
Galactose is a six-carbon monosaccharide. As a carbohydrate, galactose belongs to that class of biological [[molecule]]s that contain primarily [[carbon]] (C) atoms flanked by [[hydrogen]] (H) atoms and hydroxyl (OH) groups (H-C-OH). As a hexose carbohydrate, galactose has the same molecular formula as glucose and fructose (C<sub>6</sub>H<sub>12</sub>[[oxygen|O]]<sub>6</sub>) but a different atomic arrangement. It differs from glucose only in the position of the hydroxyl group on carbon-4 (Bender and Bender 2005). (The carbons of glucose are numbered beginning with the more oxidized end of the molecule, the [[carbonyl]] group.) In other words, galactose is an epimer of glucose, having a different configuration at only one of several stereogenic centers.  
  
 
In galactose, the first and last -OH groups point the same way and the second and third -OH groups point the other way.
 
In galactose, the first and last -OH groups point the same way and the second and third -OH groups point the other way.
Line 51: Line 51:
 
[[Galactan]] is a [[polymer]] of the sugar galactose. It is found in [[hemicellulose]] and can be converted to galactose by [[hydrolysis]].
 
[[Galactan]] is a [[polymer]] of the sugar galactose. It is found in [[hemicellulose]] and can be converted to galactose by [[hydrolysis]].
  
−
Lactose is a main dietary source of galactose for humans. Lactose is a [[disaccharide]] that consists of β-D-galactose and β-D-[[glucose]] fragments bonded through a β1-4 [[glycosidic]] linkage. The [[hydrolysis]] of lactose to glucose and galactose is [[catalysis|catalyzed]] by the [[enzyme]] [[lactase]], a [[beta-galactosidase|β-galactosidase]]. In the human body, glucose is changed into galactose in order to enable the [[mammary gland]]s to secrete lactose. The β-galactosidase enzyme is produced by the [[Lac operon|''lac'' operon]] in [[Escherichia coli|''Escherichia coli'']] (''E. coli'').
+
Lactose is a main dietary source of galactose for humans. Lactose is a [[disaccharide]] that consists of β-D-galactose and β-D-[[glucose]] fragments bonded through a β1-4 [[glycosidic]] linkage. The [[hydrolysis]] of lactose to glucose and galactose is [[catalysis|catalyzed]] by the [[enzyme]] [[lactase]], a [[beta-galactosidase|β-galactosidase]]. In the human body, glucose is changed into galactose in order to enable the [[mammary gland]]s to secrete lactose. The β-galactosidase enzyme is produced by the [[Lac operon|''lac'' operon]] in [[Escherichia coli|''Escherichia coli'']] ''(E. coli)''.
  
 
==Liver galactose metabolism==
 
==Liver galactose metabolism==
−
Galactose in the bloodstream travels to the [[liver]]. In the liver, galactose (gal) is converted to [[glucose 6-phosphate]] (glc 6-P) in the following reactions:
+
Galactose in the bloodstream travels to the [[liver]]. In the liver, galactose (Gal) is converted to [[glucose-6-phosphate]] (Glc-6-P) in the following reactions:
  
−
    ''galacto-''        ''uridyl''          ''phosphogluco-''
+
 
−
    ''kinase''        ''transferase''          ''mutase''
+
        galacto-               uridyl               phosphogluco-
−
gal -----> gal 1-P ----------> glc 1-P --------> glc 6-P
+
        kinase               transferase               mutase
−
                    ^         \
+
    gal --------> gal 1 P ------------------> glc 1 P —---------> glc 6 P
−
                  /           v
+
                            ^           \
−
                  UDP-glc UDP-gal
+
                            /             v
−
                  ^           /
+
                        UDP-glc       UDP-gal
−
                    \ <------ v
+
                            ^             /
−
                    ''epimerase''
+
                            \___________/
 +
                              epimerase
 +
 
 +
 
 +
 
 +
Enzymes that catalyze the reactions are in italic. Mutations that disable either the kinase, the transferase, or the epimerase block galactose metabolism, producing galactosemia. The cyclic reaction at the center of the diagram shows that uridyl-transferase catalyzes Gal-1-P and UDP-Glc (uracil-diphosphate-glucose) to react in such a way that the Gal displaces the Glc from its bond with UDP yielding UDP-Gal and Glc-1-P. (Biocarta)
  
 
==Clinical significance==
 
==Clinical significance==
 
Some studies have suggested a possible link between galactose in milk and [[ovarian cancer]] (Cramer 1989; Cramer et al. 1989). Other studies show no correlation, even in the presence of defective galactose metabolism (Goodman et al. 2002; Fung et al. 2003). More recently, pooled analysis done by the Harvard School of Public Health showed no specific correlation between lactose containing foods and ovarian cancer, and showed statistically insignificant increases in risk for consumption of lactose at ≥30 grams/day (Genkinger et al. 2006). More research is necessary to ascertain possible risks.
 
Some studies have suggested a possible link between galactose in milk and [[ovarian cancer]] (Cramer 1989; Cramer et al. 1989). Other studies show no correlation, even in the presence of defective galactose metabolism (Goodman et al. 2002; Fung et al. 2003). More recently, pooled analysis done by the Harvard School of Public Health showed no specific correlation between lactose containing foods and ovarian cancer, and showed statistically insignificant increases in risk for consumption of lactose at ≥30 grams/day (Genkinger et al. 2006). More research is necessary to ascertain possible risks.
  
−
Some ongoing studies suggest that galactose may have a role in treatment of [[focal segmental glomerulosclerosis]] (a kidney disease resulting in kidney failure and proteinuria). This effect is likely to be a result of binding of galactose to FSGS factor.
+
Some ongoing studies suggest that galactose may have a role in treatment of [[focal segmental glomerulosclerosis]] (a kidney disease resulting in kidney failure and proteinuria). This effect is likely to be a result of binding of galactose to FSGS factor.  
  
 
==Metabolic disorders==
 
==Metabolic disorders==
 +
{{Main|Galactosemia}}
 
There are some important disorders involving galactose.
 
There are some important disorders involving galactose.
  
−
'''Galactosemia''' is a rare [[genetics|genetic]] [[Metabolism|metabolic]] [[Disease|disorder]] which affects an individual's ability to properly metabolize the sugar galactose. Goppert first described the disease in 1917 (Goppert 1917), with its cause as a defect in galactose metabolism being identified by a group led by [[Herman Kalckar]] in 1956 (Isselbacher et al. 1956). Its incidence is about one per 47,000 births (classic type).
+
[[Galactosemia]] is a rare [[genetics|genetic]] [[Metabolism|metabolic]] [[Disease|disorder]] that affects an individual's ability to properly metabolize the sugar galactose. Goppert first described the [[disease]] in 1917 (Goppert 1917), with its cause as a defect in galactose metabolism being identified by a group led by [[Herman Kalckar]] in 1956 (Isselbacher et al. 1956). Incidence of the most common or classic type of galactosemia is about one per 62,000 births (Merck).
−
 
 
−
Normally, lactose in food (such as [[dairy]] products) is broken down by the body into glucose and galactose, and these sugars are further metabolized. In individuals with galactosemia, the enzymes needed for further metabolism of galactose are severely diminished or missing entirely, leading to toxic levels of galactose to build up in the blood, resulting in [[hepatomegaly]] (an enlarged [[liver]]), [[cirrhosis]], [[renal failure]], [[cataract]]s, and [[brain damage]]. Without treatment, mortality in infants with galactosemia is about 75 percent.
 
−
 
 
−
The fourth carbon on Galactose has an axial [[hydroxyl]] (-OH) group. This causes galactose to favor the open form as it is more stable than the closed form. This leaves an [[aldehyde]] (O=CH-) group available to react with nucleophiles, particularly proteins which contain [[amino]] (-NH2) groups, in the body. This uncontrolled reactivity gives way to glycolation. Glycolation causes disease by altering the structure of proteins in ways that were not intended for biochemical processes.
 
−
 
 
−
The only treatment for classic galactosemia is eliminating lactose and galactose from the diet. Even with an early diagnosis and a restricted diet, however, some individuals with galactosemia experience long-term complications.
 
−
 
 
−
Galactosemia is sometimes confused with [[lactose intolerance]], but galactosemia is a more serious condition. Lactose intolerant individuals have an acquired or inherited shortage of the enzyme [[lactase]], and experience abdominal pains after ingesting dairy products, but no long-term effects. In contrast, galactosemic individuals who consume galactose can cause permanent damage to their bodies.
 
−
 
 
−
'''Galactose-1-phosphate uridylyltransferase galactosemia''' (or '''Galactosemia type 1''') is the most common type of [[galactosemia]]. It is caused by a deficiency in [[galactose-1-phosphate uridylyltransferase]]. Galactose 1-phosphate uridylyltransferase galactosemia is characterized by poor growth in children, mental retardation, speech abnormality, vision impairment (due to formation of cataract) and liver enlargement (which may be fatal). Strict removal of galactose from diet is required.
 
−
 
 
−
'''UDPgalactose-4-epimerase deficiency''' involves the enzyme UDPgalactose-4-epimerase. It is extremely rare, with only two reported cases. It causes nerve deafness.
 
  
 
==References==
 
==References==
  
 
* Bender, D. A., and A. E. Bender. 2005. ''A Dictionary of Food and Nutrition''. New York: Oxford University Press. ISBN 0198609612.
 
* Bender, D. A., and A. E. Bender. 2005. ''A Dictionary of Food and Nutrition''. New York: Oxford University Press. ISBN 0198609612.
 +
*Biocarta. [http://www.biocarta.com/pathfiles/m_g1pPathway.asp Leloir pathway of galactose metabolism] Charting pathways of life. Retrieved August 4, 2008.
 
* Cramer, D. 1989. [http://www.ncbi.nlm.nih.gov/pubmed/2510499 Lactase persistence and milk consumption as determinants of ovarian cancer risk] ''Am J Epidemiol'' 130(5): 904-10. Retrieved May 11, 2008.
 
* Cramer, D. 1989. [http://www.ncbi.nlm.nih.gov/pubmed/2510499 Lactase persistence and milk consumption as determinants of ovarian cancer risk] ''Am J Epidemiol'' 130(5): 904-10. Retrieved May 11, 2008.
 
* Cramer, D., B. Harlow, W. Willett, W. Welch, D. Bell, R. Scully, W. Ng, and R. Knapp. 1989. [http://www.ncbi.nlm.nih.gov/pubmed/2567871 Galactose consumption and metabolism in relation to the risk of ovarian cancer] ''Lancet'' 2(8654): 66-71. Retrieved May 11, 2008.
 
* Cramer, D., B. Harlow, W. Willett, W. Welch, D. Bell, R. Scully, W. Ng, and R. Knapp. 1989. [http://www.ncbi.nlm.nih.gov/pubmed/2567871 Galactose consumption and metabolism in relation to the risk of ovarian cancer] ''Lancet'' 2(8654): 66-71. Retrieved May 11, 2008.
Line 99: Line 94:
 
* Houghton Mifflin Company. 1998. ''Compact American Medical Dictionary: A Concise and Up-to-date Guide to Medical Terms''. Boston, Mass: Houghton Mifflin. ISBN 0395884098.
 
* Houghton Mifflin Company. 1998. ''Compact American Medical Dictionary: A Concise and Up-to-date Guide to Medical Terms''. Boston, Mass: Houghton Mifflin. ISBN 0395884098.
 
* Isselbacher, K. J., E. P. Anderson, K. Kurahashi, and H. M. Kalckar. 1956. [http://www.ncbi.nlm.nih.gov/pubmed/13311516 Congenital galactosemia, a single enzymatic block in galactose metabolism] ''Science'' 13(123): 635-6. Retrieved May 11, 2008.
 
* Isselbacher, K. J., E. P. Anderson, K. Kurahashi, and H. M. Kalckar. 1956. [http://www.ncbi.nlm.nih.gov/pubmed/13311516 Congenital galactosemia, a single enzymatic block in galactose metabolism] ''Science'' 13(123): 635-6. Retrieved May 11, 2008.
−
 
+
* Merck. [http://www.merck.com/mmpe/sec19/ch296/ch296d.html Carbohydrate metabolism disorders—Galactosemia.] Retrieved August 8, 2008.
  
 
{{Carbohydrates}}
 
{{Carbohydrates}}

Latest revision as of 19:01, 22 August 2008


Galactose
Beta-D-Galactopyranose.svg DL-Galactose num.svg
Identifiers
CAS number [26566-61-0]
PubChem 6036
MeSH Galactose
Properties
Molecular formula C6H12O6
Molar mass 180.08
Melting point

167 degrees C

Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Galactose (Gal) is a six-carbon sugar and a monosaccharide that combines with glucose to form the disaccharide lactose, forms galactose polysaccharides in agar, is a component in various gums, mucilages, and pectins, and is also present in sugar beets. As a hexose sugar, galactose has the same formula as glucose, C6H12O6, but differs in the position of the hydroxyl group on carbon-4 (Bender and Bender 2005). Along with glucose and fructose, galactose is one of the three most important blood sugars in animals. Galactose also is known as brain sugar (Houghton Mifflin 1998).

Galactose is less sweet than glucose and sucrose. It is considered a nutritive sweetener because it has food energy. Galactose and glucose both play important roles in joining with lipids to form glycolipids and joining with proteins to form glycoproteins. Galactolipids are a major component of the membrane tissues of plants, while galactose joined in forming the more complex galactocerebrosides acts as an important component of membrane tissues in animal muscles and nerves.

Under normal conditions, the intricate coordination in the human body is remarkable, with lactose in food being broken down, via enzymes, into glucose and galactose, and these sugars being further metabolized. However, in rare cases (one per 62,000 births), this harmonious system is compromised by a genetic disorder, affecting an individual's ability to properly metabolize the sugar galactose. This leads to toxic levels of galactose building up in the blood, requiring the elimination of lactose and galactose from the diet. This condition is known as galactosemia.

Description

Glucose as a straight-chain. Galactose differs only in the position of the hydroxyl group on carbon-4.

Galactose is a six-carbon monosaccharide. As a carbohydrate, galactose belongs to that class of biological molecules that contain primarily carbon (C) atoms flanked by hydrogen (H) atoms and hydroxyl (OH) groups (H-C-OH). As a hexose carbohydrate, galactose has the same molecular formula as glucose and fructose (C6H12O6) but a different atomic arrangement. It differs from glucose only in the position of the hydroxyl group on carbon-4 (Bender and Bender 2005). (The carbons of glucose are numbered beginning with the more oxidized end of the molecule, the carbonyl group.) In other words, galactose is an epimer of glucose, having a different configuration at only one of several stereogenic centers.

In galactose, the first and last -OH groups point the same way and the second and third -OH groups point the other way.

Galactose can be found in two enantiomers, L-galactose and D-galactose. Enantiomers are two stereoisomers that are related to each other by a reflection: They are mirror images of each other. Every stereocenter in one has the opposite configuration in the other. D-Galactose has the same configuration at its penultimate carbon as D-glyceraldehyde.

Galactose is less sweet than glucose and about one-third as sweet as sucrose (Bender and Bender 2005). It also is less soluble in water than glucose.

Sources and relationship to lactose

D-galactose is found in such sources as lactose (milk sugar), agar, gum arabic, sugar beets, seaweed, and nerve cell membranes. L-galactose is found in flaxseed mucilage, snail galactogen, agar, and other such sources. Often the two forms are found together, producing DL-galactose.

Galactose also is synthesized by the body, where it forms part of glycolipids and glycoproteins in several tissues. Galactose is an important component of cerebrosides, which are glycosphingolipids that are important components in animal muscle and nerve cell membranes. Myelin is the most well known cerebroside. Cerebrosides consist of a ceramide with a single sugar residue at the 1-hydroxyl moiety. The sugar residue can be either glucose or galactose; the two major types are therefore called glucocerebrosides and galactocerebrosides. Galactocerebrosides are typically found in neural tissue, while glucocerebrosides are found in other tissues.

Galactan is a polymer of the sugar galactose. It is found in hemicellulose and can be converted to galactose by hydrolysis.

Lactose is a main dietary source of galactose for humans. Lactose is a disaccharide that consists of β-D-galactose and β-D-glucose fragments bonded through a β1-4 glycosidic linkage. The hydrolysis of lactose to glucose and galactose is catalyzed by the enzyme lactase, a β-galactosidase. In the human body, glucose is changed into galactose in order to enable the mammary glands to secrete lactose. The β-galactosidase enzyme is produced by the lac operon in Escherichia coli (E. coli).

Liver galactose metabolism

Galactose in the bloodstream travels to the liver. In the liver, galactose (Gal) is converted to glucose-6-phosphate (Glc-6-P) in the following reactions: 


       galacto-                uridyl                phosphogluco-
        kinase               transferase                mutase
   gal --------> gal 1 P ------------------> glc 1 P -----------> glc 6 P
                            ^           \
                           /             v
                        UDP-glc       UDP-gal
                           ^             /
                            \___________/
                              epimerase


Enzymes that catalyze the reactions are in italic. Mutations that disable either the kinase, the transferase, or the epimerase block galactose metabolism, producing galactosemia. The cyclic reaction at the center of the diagram shows that uridyl-transferase catalyzes Gal-1-P and UDP-Glc (uracil-diphosphate-glucose) to react in such a way that the Gal displaces the Glc from its bond with UDP yielding UDP-Gal and Glc-1-P. (Biocarta)

Clinical significance

Some studies have suggested a possible link between galactose in milk and ovarian cancer (Cramer 1989; Cramer et al. 1989). Other studies show no correlation, even in the presence of defective galactose metabolism (Goodman et al. 2002; Fung et al. 2003). More recently, pooled analysis done by the Harvard School of Public Health showed no specific correlation between lactose containing foods and ovarian cancer, and showed statistically insignificant increases in risk for consumption of lactose at ≥30 grams/day (Genkinger et al. 2006). More research is necessary to ascertain possible risks.

Some ongoing studies suggest that galactose may have a role in treatment of focal segmental glomerulosclerosis (a kidney disease resulting in kidney failure and proteinuria). This effect is likely to be a result of binding of galactose to FSGS factor.

Metabolic disorders

Main article: Galactosemia

There are some important disorders involving galactose.

Galactosemia is a rare genetic metabolic disorder that affects an individual's ability to properly metabolize the sugar galactose. Goppert first described the disease in 1917 (Goppert 1917), with its cause as a defect in galactose metabolism being identified by a group led by Herman Kalckar in 1956 (Isselbacher et al. 1956). Incidence of the most common or classic type of galactosemia is about one per 62,000 births (Merck).

References
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Types of Carbohydrates
General:
Aldose | Ketose | Pyranose | Furanose
Geometry
Triose | Tetrose | Pentose | Hexose | Heptose | Cyclohexane conformation | Anomer | Mutarotation
Small/Large
Glyceraldehyde | Dihydroxyacetone | Erythrose | Threose | Erythrulose | Sedoheptulose
Trioses
Ketotriose (Dihydroxyacetone) | Aldotriose (Glyceraldehyde)
Tetroses
Erythrulose | Erythrose | Threose
Pentoses
Arabinose | Deoxyribose | Lyxose | Ribose | Ribulose | Xylose | Xylulose
Hexoses
Glucose | Galactose | Mannose | Gulose | Idose | Talose | Allose | Altrose | Fructose | Sorbose | Tagatose | Psicose | Fucose | Fuculose | Rhamnose
Disaccharides
Sucrose | Lactose | Trehalose | Maltose
Polymers
Glycogen | Starch (Amylose | Amylopectin) Cellulose | Chitin | Stachyose | Inulin | Dextrin
Glycosaminoglycans
Heparin | Chondroitin sulfate | Hyaluronan | Heparan sulfate | Dermatan sulfate | Keratan sulfate
Aminoglycosides
Kanamycin | Streptomycin | Tobramycin | Neomycin | Paromomycin | Apramycin | Gentamicin | Netilmicin | Amikacin
Major families of biochemicals
Peptides | Amino acids | Nucleic acids | Carbohydrates | Nucleotide sugars | Lipids | Terpenes | Carotenoids | Tetrapyrroles | Enzyme cofactors | Steroids | Flavonoids | Alkaloids | Polyketides | Glycosides
Analogues of nucleic acids: Analogues of nucleic acids:


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