The primary prostaglandin-inactivating enzyme of human placenta is a dimeric short-chain dehydrogenase

1982 ◽  
Vol 2 (7) ◽  
pp. 503-508 ◽  
Author(s):  
Oi Tong Mak ◽  
Hans Jörnvall ◽  
Jonathan Jeffery

The native form of NAD-dependent 15-hydroxyprostaglandin dehydrogenase of human placenta has a mol. wt. of about 50 0002 while the subunit tool. wt. is around 2g 0002 suggesting a dimeric quaternary structure. These propertie% the amino acid composition, insensitivity to EDTA, and inhibition patterns show general similarities to other short-chain dehydrogenases. Several hormones tested did not influence the activity of 15-hydroxyprostaglandin dehydrogenase2 but an unusual activation by two anti-depressant drugs was found and may relate to the existence of a natural regulatory factor.

1982 ◽  
Vol 39 (1) ◽  
pp. 80-91 ◽  
Author(s):  
E. Burzawa-Gerard

Chemical data on gonadotropins from several vertebrate species are summarized and discussed from an evolutionary point of view. A high degree of homology has been observed between mammalian gonadotropins (LH and FSH) and thyrotropin (TSH). In non-mammalian species the existence of LH and FSH-like hormones has been demonstrated except for squamate and fish species. Especially in fish the number of GTHs is still controversial. One pituitary glycoprotein assumes various gonadotropic functions of the pituitary, and a second pituitary hormone (carbohydrate-poor) acts on fish ovarian growth. GTHs from bird, reptile, amphibian, and fish pituitaries have been purified and chemically characterized (amino acid composition, carbohydrate content). The existence of a quaternary structure has been demonstrated for several tetrapod LHs and fish GTHs. The amino acid composition of α and β subunits purified from turkey (Meleagris gallopavo), and turtle (Chelydra serpentira, Chelonia mydas) LHs and from common carp (Cyprinus carpio) and sturgeon (Acipenser stellatus) GTHs showed homology with the mammalian α and β subunits. The partial sequences of carp GTH subunits have shown that the carp GTH β was more closely related to mammalian LH β than to FSH β. Hybrid molecules could be obtained by association of heterologous subunits. The kinetics of subunit association has been studied in vitro. As compared to ovine LH, subunit association of carp GTH was more rapid and thermodependent. The subunit β seemed to determine the thermodependence. The various GTH subunits in living vertebrate probably derive from a common ancestral molecule.Key words: vertebrate gonadotropins, chemical characterizations, GTHs subunits, amino acid sequences, hybrid molecules, evolution.


1984 ◽  
Vol 222 (1227) ◽  
pp. 259-271 ◽  

Peridinin-chlorophyll a -protein (PCP) complexes isolated from three strains of the symbiotic dinoflagellate Symbiodinium microadriaticum Freudenthal have been found to occur in multiple isoelectric forms, but the pattern of isoelectric forms of PCP is characteristic of each strain. Analysis of PCP after growth of the algae from Tridacna maxima, Cassiopeia frondosa, and Rhodactis sancti-thomae at 22, 57 and 157 μmol m -2 s -1 demonstrated that the patterns remained unchanged. Determination of the native molecular mass, quaternary structure and amino acid composition of two isoelectric forms of PCP derived from algae from Anthopleura elegantissima and Rhodactis sancti-thomae showed similar native molecular masses and amino acid composition, but while PCP from the algae from A. elegantissima is dimeric, PCP from algae from R. sancti-thomae is monomeric. The potential use of PCP as a taxonomic tool in dinoflagellate systematics and the evolution of multiple forms of these pigment-protein complexes are discussed.


2009 ◽  
Vol 42 (2) ◽  
pp. 169-173 ◽  
Author(s):  
Xuan Xiao ◽  
Pu Wang ◽  
Kuo-Chen Chou

In vivo, some proteins exist as monomers (single polypeptide chains) and others as oligomers. The latter are composed of two or more chains (subunits) that are associated with each other through noncovalent interactions and, occasionally, disulfide bonds. Oligomers can be further classified into homo-oligomers (formed by identical subunits) and hetero-oligomers (formed by different subunits), and they form the structural basis of various biological functions such as cooperative effects, the allosteric mechanism and ion-channel gating. Therefore, it would be of less interest or of low priority for crystallographic scientists to crystallize a single protein chain and determine its three-dimensional structure if it is already known as part of an oligomer. However, it is both time-consuming and laborious to acquire such information on the quaternary structure attribute purely by experiment. In particular, with the avalanche of protein sequences generated in the post-genomic age, it is highly desirable to develop an automated method by which crystallographic scientists can rapidly and effectively identify which quaternary attribute a particular protein chain has according to its sequence information. In view of this, a computational method has been developed by hybridizing the approaches of functional domain composition and pseudo amino acid composition. For the convenience of crystallographic scientists, a user-friendly web server,PQSA-Pred, has been established at http://218.65.61.89:8080/bioinfo/pqsa-pred, by which the desired information can be easily obtained.


2014 ◽  
Author(s):  
Alexandra Jayne Kermack ◽  
Ying Cheong ◽  
Nick Brook ◽  
Nick Macklon ◽  
Franchesca D Houghton

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