Lobster muscle

Regnouf, E Kassab, R. Fattoum, A. Primary structure of lobster-muscle arginine kinase. Isolation and characterization of the fragments produced by cyanogen-bromide cleavage. Eur. J. Biochem., 44, 67-79 (1974)... 

Virden, R. Watts, D.C. Baldwin, E. Adenosine 5 -triphosphate-arginine phosphotransferase from Lobster muscle purification and properties. Biochem. J., 94, 536-544 (1965)... 

Assaf, S.A. and Graves, J.D. (1969). Structural and catalytic properties of lobster muscle glycogen phosphorylase. Journal of Biological Chemistry 244, 5544-5555. 

TCDF). Concentrations in lobster muscle tissues were all below detection limits of 6-20 pg/g for... 

Leung, P.S.C., Chen, Y.C., Mykles, D.L., Chow, W.K., Li, C.P., Chu, K.H. 1998b. Molecular identification of the lobster muscle protein tropomyosin as a seafood allergen. Molecular Marine Biology and Biotechnology 7(l) 12-20. 

Fig. 21. Chain trace of lobster muscle glyceraldehyde-3-phosphate dehydrogenase subunit. Stereo drawing from the work of Rossmann and colleagues [166]. Bound NAD is also shown.

Rabbit, ox, human, chicken, turkey, pheasant, halibut, sturgeon, lobster muscle 16... 

T. aquaticus, and comparison of this sequence with that of the lobster muscle enzyme shows a sequence identity of 50% which is again significantly higher than was found in comparison of bacterial and liver alcohol dehydrogenase (33) or bacterial and muscle triosephosphate isomerase (SP). 

Fig. 3. Stereoviews of the Co atom backbone in lobster muscle GAPDH (a) one subunit viewed to illustrate the NAD -binding and catalytic domains (b).the NAD -binding domain viewed in the same orientation as in (a) (c) the catalytic...

Many phosphorylases are activated by adenosine 5 -phosphate, and Michaelis constants for the binding of adenosine 5 -phosphate to the enzyme have been found. The Km for adenosine 5 -phosphate depends on the concentrations of D-glucosyl phosphate and inorganic phosphate, and decreases as their concentrations increase. Addition of adenosine 5 -phosphate has a similar effect on the Km for glycogen, D-glucosyl phosphate, inorganic phosphate, and arsenate that is, the Km values decrease as the concentration of adenosine 5 -phosphate increases. " Values of Km for adenosine 5 -phosphate of 0.2 to 1.5 fiM, 50 fiM, 60—100 fiM, 47 juM, and 25 p,M have been found with the phosphorylases from rabbit-muscle a-form, - rabbit-muscle b-form, rabbit liver, lobster-muscle b-form, and turtle heart, respectively. 

A partially purified cyclic GMP-activated protein kinase from lobster muscle was later found to have a for cyclic GMP of about 0.08 /x.M and for cyclic AMP of about 4 /aM. A cyclic AMP-activated protein kinase isolated from the same tissue had an apparent Ka for cyclic AMP of about 0.02 /J.M and for cyclic GMP of about 1.2 ptM [76]. Cyclic GMP-dependent phosphorylation of endogenous protein has been demonstrated in membranes of mammalian smooth muscle [78]. In the presence of 10 mM Mn, a half-maximal increase in the phosphorylation of these proteins occurred with 20-30 nM cyclic GMP, but ten-fold higher concentrations of cyclic AMP were required to produce the same increase in phosphorylation. 

For cyclic GMP, a cyclic GMP-activated protein kinase from lobster muscle is utilised. The cyclic GMP assay is somewhat less sensitive than the radioimmunoassay but has the advantage of the short time needed for the preparation of the binding protein 0.5 to 1 pmol of cyclic GMP can be estimated [155]. 

Apoenzyme prepared from muscle holoenzyme by treatment with charcoal is unstable and diflScult to crystallize (60, 61). Consequently, it has not so far been possible to solve the three-dimensional structure of apo-GAPDH by X-ray crystallographic methods. Suzuki and Harris (18) were able to prepare stable crystals suitable for X-ray diffraction analysis of both holo- and apoenzyme from the thermophile B. stearother-mophilus. GAPDH from this source is considerably more stable than enzyme from mesophiles (17, 18), and this stability is retained even in the absence of NAD (Fig. 9). Wonacott and colleagues (62, cf. 18) have shown that these holoenzyme crystals are orthorhombic with space group P2,2i2 the unit cell, like that of the lobster muscle enzyme, consists of four tetramers. Apoenzyme crystals were found to be monoclinic (space group P2i), and the unit cell consists of two tetramers. 

The observation by Fritz et al.. (28) that avermectin s effects on the lobster muscle could not be reversed by washing also supports the above conclusion that these effects in invertebrate systems may not be directly related to GABA itself, because free GABA would be eliminated by extensive washing. Similarly, the possibility of the involvement of benzodiazepine receptors in the action of avermectin on the American cockroach could be excluded since little effect on the benzodiazepine receptor by avermectin was found ... 

B-side Glyceraldehyde-3-phosphate dehydrogenase Lobster muscle s vn-NAD X-Ray 67... 

The activation of phosphorylase is probably due to phosphorylation of the protein molecule rather than to dimerization. Phosphorylase (a) and (b) were isolated and crystallized from lobster muscle, and their sedimentation characteristics were found to be identical. Thus, in lobster muscle, the only difference between the active and inactive forms probably resides in the presence of phosphorus in the former. It was further observed that phosphorylase (a) contains one molecule of pyridoxal phosphate per 100,000 g of protein, and that, in contrast to (b), phosphorylase (a) did not require AMP for activity. A kinase that converts the (b) to the (a) form and a phosphatase that catalyzes the opposite reaction have also been purified from lobster muscle. Phosphorylase kinase has been purified from rabbit muscle. The enzyme is much more active if it is preincubated with ATP and magnesium prior to exposure to the substrate. The activity of the preincubated enzyme can be further stimulated by heparin, glycogen, and cyclic AMP. 

When ATP is hydrolyzed by the ATPase of washed lobster muscle strips in the presence of HjO, the released inorganic phosphate is heavily labeled with 0 while the ADP is not (ISO). This indicates that hydrolysis takes place by a rupture of the terminal O—P bond brought about by a nucleophilic attack of the of HsO on the terminal phosphorus atom of ATP [Eq. (43)]. 

Abe T, Kawai N, Miwa A (1983) Effects of a spider toxin on the glutamineigic synapse of lobster muscle. J Physiol 339 243-252... 

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