LAB REPORT

Lab Report

Abstract

During the last decade, tremendous advancements occurred in the structure and mechanism of the enzyme Phosphoenolpyruvate carboxylase (PEPC). The protein consists of a three-dimensional structure. This structure of protein assimilates identical subunits of approximately 100,000 in molecular weight. Malate can be defined as a 'mixed' inhibitor of the enzyme PEPC. Malate inhibits PEPC regardless of the conditions. The inactive uninhibited undergoes numeral variations which depend on source, conditions and factors of the enzyme. This paper aims to comprehend the molecular concept of how Malate restrains PEPC. This study includes a comparison of protein structures with respect to their role in biochemical data.

Lab Report

Introduction

PEPC (Phosphoenolpyruvate carboxylase) has a significant role in the carbohydrate metabolism of plants. In order to perform its role, the enzyme is present at a critical location. PECP is present in all species of plant. It is a crucial enzyme. PECP enzyme is present in most archaea, non-photosynthetic bacteria, cyanobacteria and green algae. However, fungi and animals do not contain this enzyme.

Maize leaves contain PEPC enzyme in a large proportion. It is because of the critical role of this enzyme in C4 photosynthesis. PEPC also plays an important role in yielding inorganic phosphate and oxaloacetate. In order to yield inorganic phosphate () and OAA (oxaloacetate), PEPC acts as a catalyst. The enzyme catalyzes the complex of carbon dioxide with Phosphoenolpyruvate. This process occurs in the presence of Sodium Bicarbonate using magnesium ion as a cofactor.

The structure of PEPC contains different sites. These sites act as binding forces for each of the allosteric effectors. These sites include fructose 1, long chain fatty acids, acetyl-CoA, L-aspartate, 1, 6- bisphosphate, and others.

Another name for PEP Carboxylase is tetrameric protein. PEP Carboxylase integrates a compound of dimmers as their biologically active form. The Escherichia coli PEPC enzyme with DCDP has been acknowledged. This incorporates a substitute of the substrate PEP, and aspartate.

According to the recent research, a protein structure for the PECP maize enzyme has been determined. The enzyme integrates no substrate or inhibitor in its structure. Two monomers of this enzyme create a dimer. It, in sequence, dimerises which results into a tetramer. Due to the difference of stark in the form, these two monomers produced different conformations. These conformations enable the pdb file to integrate two monomers. This comprehension provides an understanding of the objectives of this experiment. The reason due to which Malate inhibits PEPC is that they correspond to the active conformation and the inactive inhibited conformation. Therefore, this experiment will aim at determining the differences in structure of the two monomers.

Aims

The aim of this experiment is to:

Comprehend the molecular concept of how Malate inhibits PEPC.

Compare protein structures and understand their role in biochemical data interpretation and examination of molecular mechanisms.

Discussion

PEPC activity was attempted by supervising the decline in absorbance at 340nm. The reason of this supervision was NADH oxidation in the presence of excess Malate dehydrogenase (MDH). There are two carboxylase enzymes of C4 plants which are active during the process of ...