Showing papers on "Phosphagen published in 2016"
TL;DR: It was shown for the first time that sterlet axonemal dynein ATPases have a higher affinity for ATP than do those of carp, and that spermatozoa of these taxonomically distant species use similar systems to supply energy for flagella motility, but with different efficacy.
17 citations
TL;DR: The results demonstrated that the haemolymph CgAK could serve as an important purinergic regulator to modulate extracellular ATP, which might further have an important effect on the pur inergic signaling-activated innate immune response of oyster.
15 citations
TL;DR: The lack of change in other intramuscular PCr system markers are suggestive of dysfunctions at the mitochondrial level while the impact of neuromuscular changes, lean mass cross-sectional area and differences in physical activity are also important.
Abstract: To examine age-related differences in intramuscular concentrations of adenosine triphosphate (ATP), free creatine (FCr), phosphocreatine (PCr) and total creatine (TCr) and if these differences were related to muscle performance. Forty-two healthy, non-sedentary, males between 20 and 76 years provided muscle samples to determine [ATP], [FCr], [PCr], and [TCr]. Maximal strength and endurance were assessed and correlated with intramuscular variables. Intramuscular [ATP] decreased by 13.5 % (p = 0.013) in the older cohort (18.0 ± 0.6 mmol/kg dry wt) vs. the young cohort (20.8 ± 0.9 mmol/kg dry wt) and was significantly correlated to age (r = −0.38, p = 0.008). No other differences were observed between age groups for intramuscular [PCr], [FCr], [TCr], or [PCr]:[TCr] (p > 0.05). The older cohort consumed significantly less (p < 0.05) dietary protein when compared to the young cohort. Bivariate correlations were found for intramuscular [ATP] and lower body 1RM (r = 0.24, p = 0.066), leg press volume and free creatine (r = 0.325, p = 0.036) and leg press repetitions and free creatine (r = 0.373, p = 0.015). Partial correlations controlling for age eliminated the relationship between [ATP] and 1RM while intramuscular free creatine and leg press repetitions remained significant (p < 0.05) and leg press volume approached significance (p = 0.095). These results expand upon previous observations indicative of age-related reductions in intramuscular [ATP] and dietary protein intake. The lack of change in other intramuscular PCr system markers are suggestive of dysfunctions at the mitochondrial level while the impact of neuromuscular changes, lean mass cross-sectional area and differences in physical activity are also important.
7 citations
TL;DR: It is likely that the Myzostoma AK gene lineage was lost at an early stage of annelid evolution and that Sabellastarte AK evolved secondarily from the CK gene, which is a dimer of creatine kinase (CK) origin.
Abstract: We assembled a phosphagen kinase gene from the Expressed Sequence Tags database of Myzostoma cirriferum, a basal member of annelids. The assembled gene sequence was synthesized using an overlap extension polymerase chain reaction method and was expressed in Escherichia coli. The recombinant enzyme (355 residues) exhibited monomeric behavior on a gel filtration column and showed strong activity only for l-arginine. Thus, the enzyme was identified as arginine kinase (AK). The two-substrate kinetic parameters were obtained and compared with other AKs. Phylogenetic analysis of amino acid sequences of phosphagen kinases indicated that the Myzostoma AK gene lineage differed from that of the polychaete Sabellastarte spectabilis AK, which is a dimer of creatine kinase (CK) origin. It is likely that the Myzostoma AK gene lineage was lost at an early stage of annelid evolution and that Sabellastarte AK evolved secondarily from the CK gene. This work contributes to our understanding of the evolution of phosphagen kinases of annelids with marked diversity.
5 citations
01 Jan 2016
TL;DR: This chapter illustrates how all major components of the CK system are down-regulated in human and experimental heart failure and critically evaluates the contribution to disease pathophysiology.
Abstract: The link between energy production and energy utilization is predominantly met by the creatine kinase (CK) phosphagen system. CK catalyses the transfer of a high-energy phosphoryl group from ATP to creatine to form phosphocreatine (PCr). This reversible reaction facilitates energy transfer by obviating the need for ATP diffusion, while high PCr levels provide an energy buffer when demand outstrips supply. Compartmentalization of CK isoenzymes to the mitochondria and cytosol maintain favorable levels of local metabolites to maximize the energy available from ATP hydrolysis. This chapter illustrates how all major components of the CK system are down-regulated in human and experimental heart failure and critically evaluates the contribution to disease pathophysiology. Regardless, there is growing evidence from experimental models that augmentation of the CK system may be beneficial in the ischaemic and failing heart.