Putrescine is an organic compound with the formula (CH2)4(NH2)2. It is a colorless solid that melts near room temperature. It is classified as a diamine. Together with cadaverine, it is largely responsible for the foul odor of putrefying flesh, but also contributes to other unpleasant odors.
The enzyme ornithine decarboxylase catalyzes the decarboxylation of ornithine to form putrescine. This reaction is the committed step in polyamine synthesis. In humans, this protein has 461 amino acids and forms a homodimer.
Gibberellins (GAs) are plant hormones that regulate various developmental processes, including stem elongation, germination, dormancy, flowering, flower development, and leaf and fruit senescence. GAs are one of the longest-known classes of plant hormone. It is thought that the selective breeding of crop strains that were deficient in GA synthesis was one of the key drivers of the "green revolution" in the 1960s, a revolution that is credited to have saved over a billion lives worldwide.
Nitrogen assimilation is the formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds present in the environment. Organisms like plants, fungi and certain bacteria that can fix nitrogen gas (N2) depend on the ability to assimilate nitrate or ammonia for their needs. Other organisms, like animals, depend entirely on organic nitrogen from their food.
Spermine is a polyamine involved in cellular metabolism that is found in all eukaryotic cells. The precursor for synthesis of spermine is the amino acid ornithine. It is an essential growth factor in some bacteria as well. It is found as a polycation at physiological pH. Spermine is associated with nucleic acids and is thought to stabilize helical structure, particularly in viruses. It functions as an intracellular free radical scavenger to protect DNA from free radical attack. Spermine is the chemical primarily responsible for the characteristic odor of semen.
Spermidine is a polyamine compound found in ribosomes and living tissues and having various metabolic functions within organisms. It was originally isolated from semen.
Spermidine synthase is an enzyme that catalyzes the transfer of the propylamine group from S-adenosylmethioninamine to putrescine in the biosynthesis of spermidine. The systematic name is S-adenosyl 3-(methylthio)propylamine:putrescine 3-aminopropyltransferase and it belongs to the group of aminopropyl transferases. It does not need any cofactors. Most spermidine synthases exist in solution as dimers.
The acetolactate synthase (ALS) enzyme is a protein found in plants and micro-organisms. ALS catalyzes the first step in the synthesis of the branched-chain amino acids.
The enzyme adenosylmethionine decarboxylase catalyzes the conversion of S-adenosyl methionine to S-adenosylmethioninamine. Polyamines such as spermidine and spermine are essential for cellular growth under most conditions, being implicated in many cellular processes including DNA, RNA and protein synthesis. S-adenosylmethionine decarboxylase (AdoMetDC) plays an essential regulatory role in the polyamine biosynthetic pathway by generating the n-propylamine residue required for the synthesis of spermidine and spermine from putrescein. Unlike many amino acid decarboxylases AdoMetDC uses a covalently bound pyruvate residue as a cofactor rather than the more common pyridoxal 5'-phosphate. These proteins can be divided into two main groups which show little sequence similarity either to each other, or to other pyruvoyl-dependent amino acid decarboxylases: class I enzymes found in bacteria and archaea, and class II enzymes found in eukaryotes. In both groups the active enzyme is generated by the post-translational autocatalytic cleavage of a precursor protein. This cleavage generates the pyruvate precursor from an internal serine residue and results in the formation of two non-identical subunits termed alpha and beta which form the active enzyme.
Spermine synthase is an enzyme that converts spermidine into spermine. This enzyme catalyses the following chemical reaction
Diamine acetyltransferase 1 is an enzyme that in humans is encoded by the SAT1 gene found on the X chromosome.
Spermine synthase is an enzyme that in humans is encoded by the SMS gene. The protein encoded by this gene belongs to the spermidine/spermine synthases family. This gene encodes a ubiquitous enzyme of polyamine metabolism.
Diamine acetyltransferase 2 is an enzyme that in humans is encoded by the SAT2 gene. SAT2 maintains a key metabolic glutamine/glutamate balance underpinning retrograde signaling by dendritic release of the neurotransmitter glutamate.
S-Adenosylmethioninamine is a substrate that is required for the biosynthesis of polyamines including spermidine, spermine, and thermospermine. It is produced by decarboxylation of S-adenosyl methionine.
A polyamine is an organic compound having more than two amino groups. Alkyl polyamines occur naturally, but some are synthetic. Alkylpolyamines are colorless, hygroscopic, and water soluble. Near neutral pH, they exist as the ammonium derivatives. Most aromatic polyamines are crystalline solids at room temperature.
Spermine oxidase (EC 1.5.3.16, PAOh1/SMO, AtPAO1, AtPAO4, SMO) is an enzyme with systematic name spermidine:oxygen oxidoreductase (spermidine-forming). This enzyme catalyses the following chemical reaction
Non-specific polyamine oxidase (EC 1.5.3.17, polyamine oxidase, Fms1, AtPAO3) is an enzyme with systematic name polyamine:oxygen oxidoreductase (3-aminopropanal or 3-acetamidopropanal-forming). This enzyme catalyses the following chemical reaction
Very-long-chain 3-oxoacyl-CoA synthase (EC 2.3.1.199, very-long-chain 3-ketoacyl-CoA synthase, very-long-chain beta-ketoacyl-CoA synthase, condensing enzyme, CUT1 (gene), CERS6 (gene), FAE1 (gene), KCS (gene), ELO (gene)) is an enzyme with systematic name malonyl-CoA:very-long-chain acyl-CoA malonyltransferase (decarboxylating and thioester-hydrolysing). This enzyme catalyses the following chemical reaction
Lupeol synthase is an enzyme with systematic name (3S)-2,3-epoxy-2,3-dihydrosqualene mutase . This enzyme catalyses the following chemical reaction
BpsA is a single-module non-ribosomal peptide synthase (NRPS) located in the cytoplasm responsible for the process of creating branched-chain polyamines, and producing spermidine and spermine. It has a singular ligand in its structure involved with Fe3+ and PLIP interactions. As seen by its EC number, it is a transferase (2) that transfers an alkyl or aryl group other than methyl groups (5) (2.5.1). BpsA was first discovered in the archaea Methanococcus jannaschii and thermophile Thermococcus kodakarensis and since then has been used in a variety of applications such as being used as a reporter, researching phosphopantetheinyl transferase (PPTase), and for NRPS domain recombination experiments it can be used as a model. Both (hyper)thermophilic bacteria and euryarchaeotal archaea seem to conserve BpsA and orthologs as branches chains polyamines are crucial for survival. There is also a second type of BpsA also known as Blue-pigment indigoidine synthetase that produces the pigment indigoidine and is found in organisms like Erwinia chrysanthemi. However, not much seems to be known about this variant except that it is a synthase, and it does not yet appear to be classified under an EC number.
